2000 S10 4.3L - No check engine light and no pending codes?

cwatkin
Wed, 22 Jun 2022 14:22:15 +0000
Maintenance/Repairs

My 2000 S10 with a 4.3L has started doing some strange things. Of course it was during the time my girlfriend needed to borrow it but I don’t think it is anything she has done. The truck is over 20 years old. It is going into the shop whenever the parts arrive and the mechanic has time for another issue so might just have them take care of whatever is going on.

First thing, there is a strong gasoline smell around the truck when parked. It always stinks like gas. I cannot pinpoint where the smell is coming from. Codes and pending codes have been read MULTIPLE times and there is nothing showing an EVAP code or similar.

The only code that popped while she had the truck was a throttle position sensor code. I replaced, cleared the code, and that one never returned.

Soon after I replaced the TPS, another strange problem cropped up. The engine started revving. Just being in 4th gear it was wanting to go 45mph. I was busy but had her stop at an AutoZone to have the codes read. There was nothing. I figured it might be a vacuum leak as I had to disconnect the lines to replace the TPS so checked it that night. All lines were connected and in the proper place. Again, there was not a check engine light or codes of any kind.

I ran some seafoam through the intake and through the port for the IAC and it seems much better but still revvs. I am wondering if the IAC is gummed up but wouldn’t that trigger a code?

The truck is going in for a new upper intake, spider fuel injection, and intake manifold gasket. GM is notorious for intake gasket failures on these engines and others. The mechanics said you would never re-use a 20 year old plastic intake and fuel injectors so is best to do it all at once. I figure whatever is causing the revving is probably in the upper intake so I will tell them to clean and/or replace any sensor that might cause this.

I did disconnect the battery and turn on the headlights to reset the computer before using the Seafoam but that made no difference either. It probably has a couple hundred miles or more since I did that. Again, no check engine lights or codes have returned.

Any other suggestions?

10 posts - 6 participants