1989 Chevy S-10 Missing on two cylinders

SHOOP17REDNECK

MEMBER
1989 CHEVROLET S-10

Engine problem
1989 Chevy S-10 V4 Two Wheel Drive Manual 142000 miles

I was driving home tonight and was running about 60-65 against the wind and I noticed that my began to run pretty rough. It was making a weird noise and sending alot of vibration through the whole truck. I just happened to be going past a guy who I knew had some experience with a S-10's and I stopped and asked him to help me out. We looked at it and we figured out that its not hitting on the front two cylinders. We popped off the front two wires and it didnt even phase the truck. However the back two wires if pulled off would make the truck run even worse. So we pulled the plugs and noticed they were pretty wide on the gap and pretty dirty. I changed all the plugs, wires, cap and roter in June. So we gapped them right and cleaned them off. We also made sure that the spark was going all the way through to the plug which it was. We put them back in and it still ran rough. So we went to town and bought a new set and did the same thing with the same result. Its still running really rough and on only two cylinders. My buddy said it might be the timing? Idk. Im hoping you might have an idea.

2 Replies

PEAR69

MECHANIC
1,482 POSTS

Are you sure this engine is a V-4. I've never heard of a chevy V-4. A straight 4 maybe?
Anyway, is the engine light on? Take the distributer cap off and check for any unusual wear or pitting of the contacts. Test the coil and the ignition module. Autozone or a place like that will test these things for free. I dought the timing is off because you said this happened going down the highway, unless the distributer became loose for some reason, the timing just doesn't "go off ".
Is this truck fuel injected or carburated? If injected how many injectors does it have?