mystery engine problem!

Just a shot in the dark here. Having proplems with my toyota truck - 1991 4wd ex cab 22re. Engine light goes on on occasion as engine hesitates then it goes away for a while. Sometimes the engine light doesn't go off as the engine hesitates. Diagnostic code 31 i do believe, suggests airflow meter, or exaust manifold, or o2 sensor. have had everything checked/replaced except 02 sensor. I am a stubborn do-it-yourselfer, however i have had toyota and several others look at it: Toyota wanted to replace my entire exaust system from the manifold on - w/o mentioning that price tag I got another person to look - manifold was good small leak at first pipe connection. Another tech guy told me to replace my airflow meter - got a used one. Could this leak in the pipe - before the o2 sensor cause this problem? Could a bad o2 cause this problem. If you could offer me advice I would greatly appreciate it. I know its best to see the vehicle, but it will go days sometimes w/o hesitating. And it seems that it does it up hill? Also I have replaced the plugs, wires, dist. cap, rotor, put good fuel injector cleaner in gas. All this hesitating happened a few days after I changed my fuel filter - coincidence?

Thanks for your time and thoughts

Walt
wbec@email.msn.com

replace the 02 sensor. they are notorious foe going bad. i replaced mine because the check engine was coming on and since i replaced it the light hasn't come back on.

I had a very similar problem with my 85 22RE. I got codes indicating Air Mass Sensor, ECU, O2 sensor etc. I replaced most of those parts with different ones. On a wild hair, I took the rig to a dealer for a fuel pressure check. Turns out that the fuel pump (located in the fuel tank) was bad. It gave the computer all the indications of other things that may have been bad. I replaced the pump (NAPA, around $50) and the truck runs great. Have someone, or yourself, check the fuel pressure. It's fast, easy and cheap...and you may get lucky. Good Luck. KUK

Where online can I find the troubleshooting codes for my '88FJ62? Thanks abunch!

[minipigg]

bro you do realise this thread was from 2001?

http://slowspeed.com/repair/troublecode.html