This is similar to a post i made the other day but a few things are different, please read and help.

So i did an entire tune up, plugs, wires, cap, rotor, fuel filter, air filter, trans filter, pcv. Had a 0303 code. thats gone i think it was a vacuum prob because there was a line vacuum line right above that cyl. so i put a cap on it. Now i have a 0300 code. if seems to run fine at idle but as soon as i put it in gear then it bogs down and almost dies and the CEL starts yelling at me. fuel pressure is holding strong at about 56-58.

I used autolite plugs even though i know i should have ACDelco. Could this be my problem because i have heard these engines are stubborn if ACDelco isnt used?

second issue. i pulled off the IAC and the plunger is very hard to push in and out. is this normal or does it need replaced?

Thanks in advance.

 

You may have damaged the worm gear in the IAC. It does sound like the IAC valve could be contributing to your problem, is the o ring still intact?

 

Ya i am pretty sure the o-ring was still good. I found in the Haynes manual to check for resistance across pins A and B then C and D. It should be 40-80 ohms. Is this an effective test for the IAC or is it a waste of time??

 

IAC checked good, TPS checked good, cleaned MAF sensor.