chriscrash

hello,
i am a wanna be mechanic on weekends. I just bought a new truck 1994 chev short box 4.3 ran great and now its surging, does not feel like its running at full.
I have replaced the EGR valve it was just brutal, i also did the throttle sensor. which made the gas pedal way better. but its still surging and just does not sound right. I did replace the plugs, with bosch plugs. napa gave me the plugs for the truck but they were smaller then the ones in there.
I dont want to keep chasing nothing so where should I start now?
starting to bug me.
Also the truck is dieseling now when you turn the key off but I did notice it was a little better with the new egr.
I thought timming was going on it but a mechanic said you cant time those trucks as the timing is set by the computer?
I have lots of questions.
Thanks.
Chris

chriscrash

I am thinking, maybe bring the old plug and buying the same size sort of thing. Maybe thats the problem?

geozeke

Surging is usually a sign of a fuel starvation problem. I would suggest a can of Sea Foam in the gas tank, and a new fuel filter to start. If the problem started as soon as you changed the plugs, then double check that it is right plug for your truck (check Advance Auto or RockAuto online), and also consider that one of your plugs wires might have been damaged during the plug swap. The dieseling is a sign of overheating, which could point the new spark plugs as being in a hotter heat range. Maybe a set of stock plugs are the $15 end of the investigation.....

MDTAHOE

Bosch plugs are junk. The only cars they are decent for is a European. If they look different then the original then they are probably wrong. The correct plug in any brand should look very similar to the original. I recommend putting AC Delco plugs in then see where you stand.