Hi, I'm a new to this forum. I'll try to keep this straighforward as possible since this is a troubleshooting question.

I have a 98 4 runner v6 4wd that's been great to me. One of the minor problems I have been experiencing is when I have been driving my car for a while, park at a store to do an errand, and attempt to start my car back up it stalls. This only seems to only happen when my car has been driven for a while (>20 min) and I attempt to start it up again after a brief period of time. What happens is the car starts up, I go up to about 1000 rpm, then it immediately stalls. To get around this I have to hit the gas when starting up to force it to go up to about 3000 rpm, and then when it revs down I am OK with no stalling. I also have no problem standing in traffic frequently at idle with no stalling.

From what I've read, one possible reason for this could be that I've been using a K&N air filter for a long time now. From what I read it leaks oil and could (?) cause stalling. To fix this possible problem I've ordered an amsoil air filter and plan on cleaning the air intake/throttle body.

My next idea after the previous action would be to start going through my engine sensors. Is there a EFI interface to a diagnostics machine that would be able to diagnose if I have a sensor problem?

Any help will be appreciated.

Thanks,
-Mark

 

Not too familiar with you engine but I think part of the EFI is a throttle valve position sensor?? or something close. It might be the source. This has been discussed on alt.autos.toyota.trucks
good luck,
Nathan

 

Talking with techinical assistance from toyota, they have been saying that the oil from the K&N filter is getting on the mass air flow sensor. This is causing inaccurate readings. In some cases cleaning the sensor with soapy water will fix it, while in other cases replacing the sensor is manditory. This problem can also cause the check engine light to come on and give a P0171 - Lean Malfunction DTC ( Diagnostic Trouble Code ).

Jay

 

With a izusu trooper. it turned out to be the cool air sensor on the intake manifold. Dont know if this is applicble to your 98 but hey the symtoms sure sound the same.

 

thanks for the replies guys.

I have installed the AMSOIL air filter, sure is big compared to the K&N air filter. They claim that the amount of air flow is the same as the K&N, but I don't know if that's possible. I guess the important part is not to let oil through I guess given my current problem.

I took the MAF sensor out and sprayed it out with some carb cleaner. The check engine light stayed on for a while but after a day or so came off. But unfortunately it seems the problem has not gone away. Next I will try the soap cleaning, but I don't know if this will be better than the carb cleaner.

If this doesn't work, next I'll replace the MAF sensor.

I'll reply back after I try these steps. I'll nail this thing!

Thanks again,
-Mark

 

Buy a new one.

 

Um..

Just curious, I'll probably buy a new MAF sensor regardless, but I do damage by spraying the sensor with carb cleaner? According to the can directions, it works as an oil solvent.

 

Well, the offical word is to use Soap and water. The "Hot Wire" of the sensor is coated in some sort of material. My personal opinion is that using any kind of cleaning chemical on this could deteriorate this material and ultimatly throw the sensor out of calibration.

Just a person thought.

Jay