2004 Chevrolet Suburban Misfiring-I am stumped! Help
goodforbrains
Member Posts: 1
Hi, new guy here, can someone help!
Hi, I have a 2004 Chevy Suburban "Z" 8th digit 5.3l .215,000 miles. Engine was running terrible and misfiring. Got the p0300 random misfire code. I used a timing light to check which cylinder was missing. I determined that the whole passenger side was missing. I changed out both o2 sensors on that side. and my problem was gone. I never reset the codes. I just drove it. Engine ran great. Check engine light turned itself off. That same day. I took it through for my state emissions test and passed with no problems. Engine ran great for 2 days.
On the 4th day after replacing the 02 sensors, I was driving home from work and suddenly with no warning at all, complete loss of power and smoke from high heat coming from my catalytic converters. Both were glowing at the front telling me un burnt fuel collected in there. Engine would not restart.
The following morning after completely cooling off it still would not start. Had it towed to the house. Pulled the codes and there was the p0300 code again, and a lean condition code in bank 2. Forgot the code for that off of the top of my head. Seems like there is no spark at all though. I pulled plugs from both sides and are wet with fuel. Fuel pump and filter are new (10,000) miles ago. No fuel in pressure regulator hose and there is plenty of pressure at the test fitting.
I sprayed throttle body cleaner into the intake to determine if engine would fire up. It did not. So I am kinda at a loss as to what happened, and where I should go from here. Crank sensor? Would a failing crank sensor allow fuel into the exhaust system?
I'm borowing my mother in laws hyundai and I want to give it back MORE than she wants her car back! Thanks for reading and helping!
Hi, I have a 2004 Chevy Suburban "Z" 8th digit 5.3l .215,000 miles. Engine was running terrible and misfiring. Got the p0300 random misfire code. I used a timing light to check which cylinder was missing. I determined that the whole passenger side was missing. I changed out both o2 sensors on that side. and my problem was gone. I never reset the codes. I just drove it. Engine ran great. Check engine light turned itself off. That same day. I took it through for my state emissions test and passed with no problems. Engine ran great for 2 days.
On the 4th day after replacing the 02 sensors, I was driving home from work and suddenly with no warning at all, complete loss of power and smoke from high heat coming from my catalytic converters. Both were glowing at the front telling me un burnt fuel collected in there. Engine would not restart.
The following morning after completely cooling off it still would not start. Had it towed to the house. Pulled the codes and there was the p0300 code again, and a lean condition code in bank 2. Forgot the code for that off of the top of my head. Seems like there is no spark at all though. I pulled plugs from both sides and are wet with fuel. Fuel pump and filter are new (10,000) miles ago. No fuel in pressure regulator hose and there is plenty of pressure at the test fitting.
I sprayed throttle body cleaner into the intake to determine if engine would fire up. It did not. So I am kinda at a loss as to what happened, and where I should go from here. Crank sensor? Would a failing crank sensor allow fuel into the exhaust system?
I'm borowing my mother in laws hyundai and I want to give it back MORE than she wants her car back! Thanks for reading and helping!
0
Answers
Cat flow good? Plugged or partial plugged cat can cause symptoms.
Fuel pressure good? Bad fuel pressure regulator could cause problems. Usually more noticeable on start up than running, but can also cause over pressure problems.
You have to check with a gauge, you cannot check fuel pressure by just checking pressure at the test fitting.
Hook up a gauge and know for certain what the pressure is.
You can't tell the difference between 25lbs and 60 lbs visually.
Where did you buy the 02 sensors? If not OEM, could be part of the problem.
You really need to re-check the codes now and see what you get.