Supurcar Posted September 20, 2009 Share Posted September 20, 2009 Well this is not about an RV, but a new addition to our family. I traded out of my 2007 Chevy Silverado (that I bought when gas was $5.00 gal, which increased in value) and used the increased value to trade out and pick up a 1998 Tacoma xcab 4x4 2.7 4CYL and cash out (no more payments). The truck is a high miler but I figure this 2.7 has to be bullet proof. It had one owner, and has a lift kit or leveling kit. My question is if anyone is familiar with this truck, it runs okay but seems to surge at idle and this evening it was hisitant to rev up, like a flat spot or almost a vapor lock. I am thinking a bad ox sensor or tsp sensor, I did notice by the air filter box a male and female plug that appeared to be disconnected and taped. Looks like a factory job, maybe it is for the automatic transmission models, but it plugs into the plate in the snout that connects the air filter box to the intake. Maybe I should take a picture lol. Quote Link to comment Share on other sites More sharing options...
Maineah Posted September 20, 2009 Share Posted September 20, 2009 Well this is not about an RV, but a new addition to our family. I traded out of my 2007 Chevy Silverado (that I bought when gas was $5.00 gal, which increased in value) and used the increased value to trade out and pick up a 1998 Tacoma xcab 4x4 2.7 4CYL and cash out (no more payments). The truck is a high miler but I figure this 2.7 has to be bullet proof. It had one owner, and has a lift kit or leveling kit. My question is if anyone is familiar with this truck, it runs okay but seems to surge at idle and this evening it was hisitant to rev up, like a flat spot or almost a vapor lock. I am thinking a bad ox sensor or tsp sensor, I did notice by the air filter box a male and female plug that appeared to be disconnected and taped. Looks like a factory job, maybe it is for the automatic transmission models, but it plugs into the plate in the snout that connects the air filter box to the intake. Maybe I should take a picture lol. Well I have a 97 2.7 and the only thing I have done to it other then normal service was a clutch at 207K and O2 sensors so far it has made it 245K. Mine has all ways had a flat spot at about 3,000 rpm but it comes out of it and runs fine. I think yours could use a fuel filter and a good going over don't know what your wire might be I'll look at mine and see if it has one. An O2 sensor will throw a code it's new enough to have an OBD2 port so if you can get some one to scan it it may tell you some tales as it will run in real time. Quote Link to comment Share on other sites More sharing options...
Supurcar Posted September 21, 2009 Author Share Posted September 21, 2009 Yes it has a diagnostic port, like I wrote I think there is something on the snout by the airbox that plugs in. I believe it to be an air flap that may open and close to slightly choke it during warming cycle. I think it may be engaging even after it is warmed up, but I am guessing. I will start with the fuel filter like you suggested, I already changed the air filter. I tried to pull the spark plug wire but it separated so I could not pull the wire off the plug. Is there a trick to this? Quote Link to comment Share on other sites More sharing options...
Supurcar Posted September 21, 2009 Author Share Posted September 21, 2009 Here are a few pics, not s drip of oil anywhere so it is very tight. I ran some feul system deep cleaner, changed the oil, cleaned the battery posts, and it seems to run a lot better. I have failed to find the fuel filter, it is not in plain sight. Quote Link to comment Share on other sites More sharing options...
Supurcar Posted September 22, 2009 Author Share Posted September 22, 2009 Well I changed the plugs,they just made the spark plug wires barely long enough to reach is all. I had a tough time getting them out, but finally got them. Autozone was nice enough to put my truck on a code reader and it said I had a lean bank 1 error. Which amount to several possibilities, the TPS, Ox sensor (fuel rail), Vaccum leak, or the airbox sensor and I forget the name of it but it is the one in the picture, and I noticed there is another plug that is disconnected in those pictures, if anyone knows what that is for. I started by removing and cleaning the airbox sensor, as it was the most expensive to replace. I put it back on and my running conditions seemed to minimize, still a somewhat rough idle (smooth compared to my Sunrader), but now I can floor it and it takes off. If this did not cure the issue I will replace the TPS and see what happens. I almost think the catalytic converter may be plugged. The exhaust tip it real black with soot inside. Quote Link to comment Share on other sites More sharing options...
Maineah Posted September 23, 2009 Share Posted September 23, 2009 Well I changed the plugs,they just made the spark plug wires barely long enough to reach is all. I had a tough time getting them out, but finally got them. Autozone was nice enough to put my truck on a code reader and it said I had a lean bank 1 error. Which amount to several possibilities, the TPS, Ox sensor (fuel rail), Vaccum leak, or the airbox sensor and I forget the name of it but it is the one in the picture, and I noticed there is another plug that is disconnected in those pictures, if anyone knows what that is for. I started by removing and cleaning the airbox sensor, as it was the most expensive to replace. I put it back on and my running conditions seemed to minimize, still a somewhat rough idle (smooth compared to my Sunrader), but now I can floor it and it takes off. If this did not cure the issue I will replace the TPS and see what happens. I almost think the catalytic converter may be plugged. The exhaust tip it real black with soot inside. There are 2 sensors bank 1 is an O2 sensor the other one is an air/fuel sensor (the sensor closest to the engine is bank 1)If there is a sensor in the air box it is an ambient temp sensor. Your picture is of a mass air flow sensor and the unplugged wire looks like a Toyota tape job it may go to some thing you don't have. If you are still having running problems the OBD2 port will allow you to check the sensors while the truck is running there are quite a number of parameters just about ever thing you can think of. If you check your bank 1 sensor it will read voltage, the voltage at idle should be very active ranging from .1 to .9 volts and any thing in between if it is not active the sensor should be replaced. Quote Link to comment Share on other sites More sharing options...
Maineah Posted September 23, 2009 Share Posted September 23, 2009 I doubt if your cat is plugged it would be absolutely gutless, soot is pretty normal. Quote Link to comment Share on other sites More sharing options...
Tom W Posted September 23, 2009 Share Posted September 23, 2009 If your gas millage is normal I would think the Converter is ok, one way to check is taking the temp before & after converter should be a lot hotter down stream 100deg or more then closer to eng these temps will be in the 200 to 300degs or more at idle. I would check for vacuum leaks by spraying carb cleaner or something in the area's in question be careful flammable and you should notice a change in Rpm. Intake manifold leaks can cause all kinds of Problems and codes and for some reason gets ignored. Quote Link to comment Share on other sites More sharing options...
Supurcar Posted September 23, 2009 Author Share Posted September 23, 2009 There are 2 sensors bank 1 is an O2 sensor the other one is an air/fuel sensor (the sensor closest to the engine is bank 1)If there is a sensor in the air box it is an ambient temp sensor. So bank one is the sensor that is on the fuel rail, or right next to the engine and does it have a vacuum loines as well? I know there is no vacuum leaks already, I checked it at work, and I use the old reliable carb spray test as well at home. The TPS is the one on the throttle body and that is what most people say is the culprit most of the time. It is actually running real good now, just a little rough idle and very small hesitation if any at all. So I think based on what you said that bank1 is the one on the engine that is one I will replace if my check engine light comes on again. Autozone says it is about $97, the TPS is only $50. Thanks for the info you guys, I am absorbing all of this before I start wrenching lol. The most amazing thing about this truck is that there is not a drop of anything leaking and it has 158,000 miles; only dust everywhere. Quote Link to comment Share on other sites More sharing options...
Maineah Posted September 23, 2009 Share Posted September 23, 2009 So bank one is the sensor that is on the fuel rail, or right next to the engine and does it have a vacuum loines as well? I know there is no vacuum leaks already, I checked it at work, and I use the old reliable carb spray test as well at home. The TPS is the one on the throttle body and that is what most people say is the culprit most of the time. It is actually running real good now, just a little rough idle and very small hesitation if any at all. So I think based on what you said that bank1 is the one on the engine that is one I will replace if my check engine light comes on again. Autozone says it is about $97, the TPS is only $50. Thanks for the info you guys, I am absorbing all of this before I start wrenching lol. The most amazing thing about this truck is that there is not a drop of anything leaking and it has 158,000 miles; only dust everywhere. Nope it's in the exhaust pipe the one closest to the engine is bank 1 the other one is closest to the cat. Why do you think it needs a TPS? Usually a bad one makes them run pretty bad. With any engine management system parts are expencive if you just keep replacing them until you fix some thing if you can get a scanner hooked up it's an easy test to check the TPS they are mechanical no electronics so they either work right or they don't. MY old bomb has 240K and it's so dry it's rusty the oil comes out about as clean as it goes in, the 2.7 would make a nice Toy home engine! Quote Link to comment Share on other sites More sharing options...
Supurcar Posted September 24, 2009 Author Share Posted September 24, 2009 Nope it's in the exhaust pipe the one closest to the engine is bank 1 the other one is closest to the cat. Why do you think it needs a TPS? Usually a bad one makes them run pretty bad. With any engine management system parts are expencive if you just keep replacing them until you fix some thing if you can get a scanner hooked up it's an easy test to check the TPS they are mechanical no electronics so they either work right or they don't. MY old bomb has 240K and it's so dry it's rusty the oil comes out about as clean as it goes in, the 2.7 would make a nice Toy home engine! Well I guess it is moot, I had it scanned 2 days ago and it read "bank1 lean", and they gave me some causes options to remedy the problem. Poor fuel pressure, Mass Air flow sensor, vacuum leak, the two ox sensors, and finally the TPS in that order. I wanted to do the cheap stuff first and got a bottle of mass airflow cleaner (just expensive carb cleaner really) and I took the thing off and sprayed it out, and I ran some thru the fuel injection for good measure (this was yesterday) and so far so good. It runs great and now has full throttle tho not much torque really. In the past the check engine light would have come on by now so I must assume I fixed it for free. It the light does come on I will replace the bank1 ox sensor. Have you done any mods to the engine or exhaust? I think my motorhome has a similar mass air flow sensor just an older design so I will get to spraying that one as well, I read about a lot of running conditions that may be cause by this little sensor being plugged or dirty. YES, I would love to have this 2.7 engine in my TMH. Quote Link to comment Share on other sites More sharing options...
Maineah Posted September 25, 2009 Share Posted September 25, 2009 Well I guess it is moot, I had it scanned 2 days ago and it read "bank1 lean", and they gave me some causes options to remedy the problem. Poor fuel pressure, Mass Air flow sensor, vacuum leak, the two ox sensors, and finally the TPS in that order. I wanted to do the cheap stuff first and got a bottle of mass airflow cleaner (just expensive carb cleaner really) and I took the thing off and sprayed it out, and I ran some thru the fuel injection for good measure (this was yesterday) and so far so good. It runs great and now has full throttle tho not much torque really. In the past the check engine light would have come on by now so I must assume I fixed it for free. It the light does come on I will replace the bank1 ox sensor. Have you done any mods to the engine or exhaust? I think my motorhome has a similar mass air flow sensor just an older design so I will get to spraying that one as well, I read about a lot of running conditions that may be cause by this little sensor being plugged or dirty. YES, I would love to have this 2.7 engine in my TMH. I’m a little skeptical about MAF sensor cleaners the MAFs are a bit fragile and really they are self cleaning. The late 90s pickups were in my opinion were geared way too high so it makes the truck seem sluggish I used to tow a popup camper with mine and it was as slow going up hills as my MH my 94 4X4 gearing was far better. Until I replaced the O2 sensor mine would throw engine codes off and on until it finally gave me a definitive O2 code I replaced the bank 1 sensor and it has not come on since. Quote Link to comment Share on other sites More sharing options...
Supurcar Posted September 25, 2009 Author Share Posted September 25, 2009 I'm a little skeptical about MAF sensor cleaners the MAFs are a bit fragile and really they are self cleaning. The late 90s pickups were in my opinion were geared way too high so it makes the truck seem sluggish I used to tow a popup camper with mine and it was as slow going up hills as my MH my 94 4X4 gearing was far better. Until I replaced the O2 sensor mine would throw engine codes off and on until it finally gave me a definitive O2 code I replaced the bank 1 sensor and it has not come on since. Well with 158,000 miles I may just do that as a pre-emptive move as it (bank1 sensor) will go out at some point anyway. At least I saved the $165 a shop wanted to fix the issue which would have been a guess on their part anyway. So far so good, still no check engine light, and it runs real good. The MAF cleaner is supposed to be real gentle, compared to Carb Spray I guess. And yes I try to keep the RPMs up or else it will lug when shifting. Quote Link to comment Share on other sites More sharing options...
sepling Posted November 3, 2009 Share Posted November 3, 2009 I've helped two friends replace the TPS on their Toy trucks and solved this type of problem. Before you replace it, test it. Google "toyota tps tests" and use a multimeter. They can also be adjusted which might fix your problem. This can also be done with a multimeter. It seems like the return spring in the TPS goes bad and there is quite a delay between when the throttle actually opens or closes and when the computer THINKS it's opening or closing. In the mean time you are running really rich or really lean and your o2 sensors do their best to accomodate it. Symptoms on my friends trucks included hesitation off idle and bad fuel economy. Open throttle was fine, just going between closed and partially open seemed to be the problem. Of course you always see the fix in things you've fixed before. It could be a totally different problem. Quote Link to comment Share on other sites More sharing options...
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