misfire question

[eightcylS10]

how much does a piston misfiring hurt horsepower? im wondering becasue today i had a hard time beating a 2000 alero and my truck is misfiring really bad, i have a HO 305 in my s10, thanks

[chevytrucks92]

It's gonna hurt it alot man. Your truck is out of time for some reason (either you have a dead/bad plug, bad wire, bad distributor cap) and when you get an engine out of time, even if its only slightly out, you're loosing hp.

First check the distributor cap for any carbon. If it looks bad, change it and the rotor and your problem will probably be cured. Then check each plug wire for any cracks.

Then check the timing on your truck (with a timing light, if you don't know how, get someone who does). If its out of time, then there is your trouble, if not, then you've got other trouble.

You could have a dead cylinder (or two) (probably caused by a dead plug, but could be other things). A quick and easy way to check for this is to take a crayon and while the truck is running (and make sure its up to normal operating temp.), mark on each header pipe; the ones that melt the crayon are firing, the ones that don't are not. This will NOT work however if you just have factory exhaust manifolds.

If you find any that are dead, check the plug and wire for that cylinder. If its bad, change it. If not, then you have other (could be serious) problems, like maybe a stuck valve, bent pushrod, bad lifter or broke rocker arm.

Worst case scenerio is a stuck valve-you'll probably have to take it to a machine shop to get that fixed. If its a bent push rod, bad lifter, or broke rocker arm, then its not REAL serious, and will be an easy fix (unless the pushrod is broke and you can only find one piece-and changing a lifter will involve alot of disassembly).

[eightcylS10]

thanks for the reply, but i checked all my wires and i found that i had 2 semi-loose wires, 2 loose plugs, and one plug was the wrong size for the engine(luckily it was too short instead of too long).

[chevytrucks92]

You're welcome, and that will do it every time, lol.