I have a 94 XLT with 90,000 miles. Started having numerous starting problems and driveability problems. I have fixed all but 1 problem. Sometimes when I start it up the engine will idle very low and surge erratically. After driving for a couple of blocks it will start running normal again. This may not happen again for another week but it seems to be getting worse. The problem also seems to be worse when the engine is cold. Due to this and other problems I have replaced the ignition module, MAF, TPS, DPFE (EGR PRESSURE SENSOR- I THINK), Bi metal temp sensor in air filter housing. So far by the time I read my error codes the problem is gone and there are no codes except 111. I bought my code reader from Autozone. The idle air valve shaft seems to be free and not stuck as well as the EGR valve. This is driving me crazy! Please help!! Cliff

I'd replace the IAC valve.

I have considered the IAC but would it make noise if it was going out? I read my codes again last night since my wife told me it was acting up again and it gave me a 116 (engine coolant temp sensor error). It was not a hard code but it was the one that is supposedly current. Forgive me if I use the wrong terms. I read the code but I did not warm up the engine first and I am wondering if this code is still valid for that reason. Of course the idle problem had disappeared by the time I got home. Will look at it again tonight after work. Thanks for your help.

Not sure what you mean by "hard" or "current", but a code 116 in KOEO or KOER means that the ECT was out of range at the time the test was performed. If the truck wasn't warmed up, that would explain the code.

Sounds like you have an intake or vacuum leak.