Truck Misfire

[john gaddis]

I own a 1994 GMC Yukon, 5.7L TBI. If my alternator is not putting out enough amps to meet peak demand, can this cause the engine to misfire? Mainly noticeable at low speeds.

 

[Jeffry Skidmore]

one of my buddy's has a GMC truck that has been having a similar issue but I cant remember what he did to solve/treat it. I'll call him later, and get back to you on here.

 

[TOMMY RICH]

Plugs, wires, distributor cap or leaky injectors can cause a missfire.

Is it throwing a code or is the SES light on?

My 94 goes thru a dizzy cap about every other year...they are noted for wear and condensation inside the cap. I'd look there first...

 

[Chris Owenby]

Like tee said plugs wires cap button and even a vacumm leak can cause this. When was the last time you did a tune up? Like tee said is it throwing a check engine light? If it is, its a obd 1 and you can pull the codes with a paper clip. Just let us know

 

[Jim B]

Tee,

have you tried an accel cap and rotor yet? Back when i had a gm with the HEI ignition they were the only ones that lasted. The normal aftermarket and even the delco ones corrode badly on the terminals. The accel ones are gold plated and last a ton longer. If you havent tried one yet you might want to look into it.

 

[VA Chris]

what is the weather like when it happens? rainy or even damp. Plug wires could be the culprit wet or dry ,but if it only happens when it is damp I would bet on it.



AAMCO had to spot me a free transmission rebuild after they diagnosed my stutter/miss as a bad tranny and afterwards found a bad plug wire.

 

[john gaddis]

I use Accel cap, rotor, plug wires and MSD coil. Problem most often occurs when stopped at traffic light with ac on. The moment I turn the ac off, engine smoothes out. Also, I have dual electric fans which supposedly draws 28 amps.

 

[TOMMY RICH]

I have dang near Accel evrything from coil to wires to shorty header plugs cuz the stock AC's are too hard to get out with headers.

Let us know how it comes out