Hey guys I drive a '91 s10 blazer 4.3 tbi and my check engine lights been coming on and off. Just to give a few details, it seems like the light is more prone to turn on when the engine is warm, and it comes on more when im stopped, let off gas, braking, or driving below 50 mph.

It's also surging like crazy. I had it in drive, complete stop, let off my brake and it sped up to 30+ mph without pressing gas at all!! It also idles real high. When I drive above 50 mph, it handles a little better and smoother, and the ses light turns off. Then when I brake to 45 or lower, the light comes back on.

Couple things I plan on doing tomorrow are my wires and clean out my EGR valve. I really don't wanna have to do my plugs cuz theyre so inconveniently placed, and i already did em less than 50k miles ago but i will if i have to. If anyone has any suggestions or similar experiences any help is appreciated!

 

I would drive up to Autozone and have them pull the codes and go from there. Otherwise you're just stumbling around in the dark.

EDIT: Just noticed this is in 1st gen tech lol. I believe you can use paperclips to get the codes on OBDI vehicles but I'm not sure exactly how to do it. Google would probably come up with a lot of walkthroughs.