That's why I always say stick with stock ignition parts. My 91 S10 never ran right with aftermarket plugs. Put standard delco plugs in and it ran like a swiss watch. Amazing.

 

Good news. That's why I asked if it was just a 'cold' problem. I guess if the IAC is dirty enough it can lead to a code.

 

glad you figured it out... kinda an old thread... but i wanted to ask something....

what was the fix with the evap 440 code? I'm getting the same thing and i have a tremendous amount of pressure when i take the gas cap off... was it just an evap malfunction? I'm wondering if mine is stuck closed... is it just that small canister on top of the intake manifold?

 

I dont know what turned off the codes...after I cleaned the IAC and plugged everything back in and fired her up...there was no SES...I had that code for sometime tho...440...Im very puzzled

 

MY truck did the same thing. I also found it was cheap gas. I use Shell 93 exclusively and I have no problems.