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99 Sub. P0300 Random Misfire I need help


JTnOKC
08-21-2005, 06:01 PM
My 99 Suburban 5.7 2WD is showing a P0300 code and I cant fix it. The engine is very sluggish, shaking and there is a popping not unlike a muffled backfire at idle. The problem came on as I was pulling off the highway and the change was rapid. I have changed: fuel filter, ignition module, plugs, plug wires and had a Berryman direct to PCV injector cleaning done. None of these things have helped. The engine does seem to run better right after I erase the P0300 code but as soon as I get underway again the SES light comes back on and engine gets back to old antics. Any help would be greatly appreciated. JT

I added a new coil tonight with no effect. Can anyone help me?

crownedroyal
08-22-2005, 09:52 PM
Might want to check the egr to see if it is working properly.

JTnOKC
08-23-2005, 08:43 PM
O2 sensors..... O2 told timing to screw up. Remove O2 sensors and shes back to normal, actually better with all the new crap I bought;)

chuck's
08-24-2005, 10:24 PM
Check this thread about misfire.It may be the cause of your problem.www.automotiveforums.com/vbulletin/showthread.php?t=173590 most people end up replacing the cam position sensor.
chuck's

ibew112
08-28-2005, 07:37 PM
Check this thread about misfire.It may be the cause of your problem.www.automotiveforums.com/vbulletin/showthread.php?t=173590 most people end up replacing the cam position sensor.
chuck's

I had to change out mine 2000 olds ses light with a misfire code, $60 bucks easy to change.

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