Engine misfire detected engine code HELP

Airforce wrench · 02-20-2008, 03:20 AM

Driving down the road and my truck started missing pretty bad, no power. The engine light started flashing. It is an 02 chevy 5.3 with 95000 miles. I made it to the hobby shop we have on the base and hooked it to the scanner and it said oxygen sensor bad, which has been bad for awhile just no time to get into it, and engine misfire detected.

I changed plugs and fuel filter i figured i would start simple and cheap, but that didn't help. I don't know much about the igntion systems on the newer vortecs, and don't want to dump a bunch of money into something that won't help. any thoughts? Thanks

z07 · 02-20-2008, 04:17 AM

Look at the ignition wires while the engine is running in total darkness. If you see any spark you've got a bad wire. Make sure that the plug wires are in their looms and routed correctly. Pull the plugs and compare them to each other. If any look odd compare it to one of the many online sparkplug diagnostic charts also found in the back of every Haynes/Chilton book. Measure the resistance of each plug wire. Correct values can be anywhere from 1k to 4k ohms per foot so look for any wire that has a resistance that is very different from the others.

If the loss of power were due to a failed O2 sensor it would only show up in closed loop so you wouldn't find any loss of power when you first start the engine cold(open loop).

With a mechanic's stethoscope, $10 at harbor freight et al, listen to the fuel injectors. If one sounds different from the others then swap it with another to see if it is the injector or the harness.

Running the engine with an inop O2 sensor isn't good for the cat. I hope it isn't clogged.

Thank you for serving your country.

keithr0005005 · 02-21-2008, 08:13 PM

a burnt up o2 sensor will cause the truck to fall on its face. find out which one is bad and switch it out. they are around 90 bucks.

02-20-2008, 03:20 AM	#1
Airforce wrench Junior Member Join Date: Feb 2008 Location: Yigo Guam Posts: 3	Engine misfire detected engine code HELP Driving down the road and my truck started missing pretty bad, no power. The engine light started flashing. It is an 02 chevy 5.3 with 95000 miles. I made it to the hobby shop we have on the base and hooked it to the scanner and it said oxygen sensor bad, which has been bad for awhile just no time to get into it, and engine misfire detected. I changed plugs and fuel filter i figured i would start simple and cheap, but that didn't help. I don't know much about the igntion systems on the newer vortecs, and don't want to dump a bunch of money into something that won't help. any thoughts? Thanks

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02-20-2008, 04:17 AM	#2
z07 Senior Member Join Date: Feb 2008 Posts: 176	Look at the ignition wires while the engine is running in total darkness. If you see any spark you've got a bad wire. Make sure that the plug wires are in their looms and routed correctly. Pull the plugs and compare them to each other. If any look odd compare it to one of the many online sparkplug diagnostic charts also found in the back of every Haynes/Chilton book. Measure the resistance of each plug wire. Correct values can be anywhere from 1k to 4k ohms per foot so look for any wire that has a resistance that is very different from the others. If the loss of power were due to a failed O2 sensor it would only show up in closed loop so you wouldn't find any loss of power when you first start the engine cold(open loop). With a mechanic's stethoscope, $10 at harbor freight et al, listen to the fuel injectors. If one sounds different from the others then swap it with another to see if it is the injector or the harness. Running the engine with an inop O2 sensor isn't good for the cat. I hope it isn't clogged. Thank you for serving your country.

02-21-2008, 08:13 PM	#3
keithr0005005 Senior Member Join Date: Jan 2008 Posts: 156	a burnt up o2 sensor will cause the truck to fall on its face. find out which one is bad and switch it out. they are around 90 bucks.