multicylinder misfires

thederelict · March 15, 2004

i have a 1998 silverado 1/2 ton with the 5.0ltr. it has developed, overnight, a low rpm sputter/shudder. it clears somewhat as you drive. the service engine soon light stays lit, flashes at speed. i have replaced: plugs, wires, fuel and air filters. where else should i look?

citydriver · March 15, 2004

When the CHECK ENGINE light goes on,it stores a trouble code in the computer..If you can get your hands on a good service manual,and read the code,that may help point you in the right direction...also if this started after you changed those parts,re-trace your steps to see if maybe you may have forgotten to hook somthin back up,or even possibly knocked somthin outa place ex:vacuum line

vortec350 · March 15, 2004

I know you are goin to think I am crazy but mine did this and it stored a PO403 which is a random misfire on cylinder 3 and it came out be a bad fuel pressure regulator.It was runnin way to rich.I replaced it ans it was fine and still is.

Wingnut · March 15, 2004

You should go down to your local auto parts store, and have them check the code. Most of them will hook up to the truck, and tell you what the code means for free.

Call them first, just to make sure. But just about all of them around here will do it.

electromag8 · March 18, 2004

My boss had a similar problem on a 97" with a 305ci After taking it to the dealer, who replaced the fuel pump, pressure regulator, checking intake gaskets, and cleaning the injectors. Did not fix the problem, dealer said to replace the engine!!! This was 2 years and 65,000 miles ago. Long story short, we picked up the truck, replaced the distributer cap and rotor and it ran like a top!!!

electromag8 · March 18, 2004

My boss had a similar problem on a 97" with a 305ci After taking it to the dealer, who replaced the fuel pump, pressure regulator, checking intake gaskets, and cleaning the injectors. Did not fix the problem, dealer said to replace the engine!!! This was 2 years and 65,000 miles ago. Long story short, we picked up the truck, replaced the distributer cap and rotor and it ran like a top!!!