I've been dealing with a motor surge with my 99 Silverado for too long to mention. Code P0300 (multiple cylinder misfire) comes up every time it pops the light on. I've had it diagnosed. So far all the tell me is that I should put new wires/plugs/coils on it. They told me 5 of the 8 coils are firing weak. Recent work includes a new evap canister and vent valve. New EGR valve New fuel filter and motor vac. Recent checks include: Fuel pressure, cat converter back pressure, both checked fine. Less than a year ago we replaced the MAF sensor. Fuel pressure regulator, temp sensor. Plugs/wires and alternator are all less than 2 years old. Wires and plugs are OEM equipment. Next move will be to replace the evap purge valve on the intake. I hear there is info on ALL DATA regarding this component. The truck starts great and runs fine at idle, you can seldom tell it's running at an idle. When you put it in drive and put your foot on the gas...there is hesitation. No sputtering or backfiring. At highway speeds, the shudder starts and gets worse when you attempt to accelerate. This started as a subtle symptom and has gotten worse over time. If anyone has any information regarding this issue, please spill the beans and tell me what the heck is going on! I've just about had it!!
i have taken this vehicle to two Chevy dealers and have yet to find a solution. They tell me that my computer is fine and there is no problem. When I picked my truck up from Lott Mathers in Haines city Florida they told me that it was ready to go and charged me $100.00. I barely made it home. Every sensor on the truck has been changed as well as the distributor and the computer. This truck just had a $8000.00 custom paint job and won't go down the road.
- Thomas Hallmann 6.,
Winter Haven, FL, US
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I've been dealing with a motor surge with my 99 Silverado for too long to mention. Code P0300 (multiple cylinder misfire) comes up every time it pops the light on. I've had it diagnosed. So far all the tell me is that I should put new wires/plugs/coils on it. They told me 5 of the 8 coils are firing weak. Recent work includes a new evap canister and vent valve. New EGR valve New fuel filter and motor vac. Recent checks include: Fuel pressure, cat converter back pressure, both checked fine. Less than a year ago we replaced the MAF sensor. Fuel pressure regulator, temp sensor. Plugs/wires and alternator are all less than 2 years old. Wires and plugs are OEM equipment. Next move will be to replace the evap purge valve on the intake. I hear there is info on ALL DATA regarding this component. The truck starts great and runs fine at idle, you can seldom tell it's running at an idle. When you put it in drive and put your foot on the gas...there is hesitation. No sputtering or backfiring. At highway speeds, the shudder starts and gets worse when you attempt to accelerate. This started as a subtle symptom and has gotten worse over time. If anyone has any information regarding this issue, please spill the beans and tell me what the heck is going on! I've just about had it!!
P0300? Multiple Cylinder Misfire. -- Vacuum leak? Fuel Injectors? 5 bad coil packs?
- rajahnme, Milwaukee, WI, US