THE_KID

My 1991 4runner with the 22re motor starts up just fine when its cold. once it warms up i have to constantly keep my foot on the gas or it will die. as it warms up the idle will get worse and worse (400-500 RPM) till the engine just shuts off. if I cruise 65+ on the freeway for an hour (my weekly commute) it will high idle at 1700 RPM as I pull off the freeway. When I hit the brakes the idle will jump from 1100-1500 RPM. It will shut off at every red light unless I give it a little gas when it warms up when driving in town. mileage is down do 15 on the highway and 10 around town. bought the rig at 240K and it ran fine getting 20+ MPG. now its close to 270K and running really bad. Check engine light is on and I'll run the codes tomorrow and have another update. Radiator cap is leaking too. Ill get a new one tomorrow. Its missing the donut gasket between the downpipe and cat too.

Any help is appreciated. thanks in advance.

mental

Sounds like an oxygen sensor to me, the codes should tell you that but I'd also check for a vacuum leak.

THE_KID

codes 24 and 31 are coming up

toyota4x4907

Doing this from memory-

24 is lean mixture read from the Oxygen sensor in the exhaust. Having no gasket there is drawing in fresh air, the O2 sensor is reading a lean condition, so the ECU is compensating by dumping more fuel in, giving you a crappy running motor and poor MPG.
31 has to do with the AFM, if I remember correctly. I had this code on my '88 4runner when I first bought it. The plug was not attached enough to get a good reading to the ECU, so it ran like crap, sometimes shutting off after a few seconds.
Has the CEL been on since you bought the rig? The code 31 could be an old stored code from the previous owner.

toyota4x4907

FSM:

http://www.ncttora.com/fsm/1990-1995...es/repair.html

THE_KID

The CEL came on about a year ago and I bought the rig 3 years ago. I forgot to mention that when the engine is at operating temperature there is a clicking sound coming from the glove box area or just below it. Every time I give it gas there is a click and every time I take my foot off the gas there is a click and the engine dies. could this just be a bad relay or something?

toyota4x4907

Er...

I was wrong on the codes... Found the FSM codes....

http://www.ncttora.com/fsm/1990-1995...e/diagnosi.pdf

24 is Open or short in intake air temp. sensor circuit for 50 msec. or more.

I'm not quite sure about that one... Considering you have both 31 and 24, and they both have to do with the AFM, You might need a new AFM...

http://www.ncttora.com/fsm/1990-1995...e/volumeai.pdf

toyota4x4907

Get access to the ECM behind the passenger's kick plate. try to determine if the clicking is coming from the ECU or more from the engine bay. Could be a relay in the fuse block under the hood. access the fuse block there, give it gas to where it would click. Listen to see if the clicking is from there...

THE_KID

thanks for the links. Ill do some more research and trouble shooting and have another update soon

THE_KID

another update. took a look under the hood after a long drive and the idle screw was completely unloosened. took it on a short drive the next day and the idle screw was completely closed. is there supposed to be a spring or something holding the idle screw in place? what would cause the idle screw to spin on its own?

The MAN

I don't think it's supposed to move at all....

dark_fairytales

here is what i suggest. first off, if your O2 sensor is more then 12 months old, replace it. O2 sensors last longer then 12 months but are not guaranteed to continue working longer then 12 months and are common to fail in the period time, due to heat cycle issues. Second try to get in contact with another local YT member so you can swap AFM's too see if that is the issue. Then check to see if the TPS is still good or needs adjustment. After all that I would suspect the Idle Air Control Valve .

Your idle screw should not move unless you move it your self. So check that out.

THE_KID

i just put a good amount of teflon tape around the idle screw and it stays in place now. also reset the efi and its not throwing anymore codes. i barely drove it though. still gotta see if my mileage improves or if the check engine light comes on again.