THey all,
03 'hoe 5.3 flex...
Decided to do some routine maintenance on the beast - plugs, wires, air filter - and afterwards the engine is running like crap, most notably at idle. On the highway the truck seems to have power and is smooth...at idle the engine runs slightly lumpy and, listening to the exhaust, it is obvious that there is a misfire.
I hooked up my scanner and go the reliable p0300 code but that does not tell me much. I cannot see it being the intake manifold gasket because I've changed that and because I tested it by spraying carb cleaner around the engine with no change; it doesn't seem like there is a vacuum leak at all. The live data on the scanner shows a defective O2 sensor on B1S2 (pegged at about 835mv). The other sensors seem fine though B2S2 seems a bit sluggish. The fuel trims are slightly negative ~ -3.5 on average. Would a -3.5 stft really cause a noticeable issue?
The engine seemed to run fine with the old plugs, single Platinum NGK plugs that were in it. I changed them because they were old and the center electrode was essentially gone on all of them. I changed the plug wires because some of them ripped when I removed them.
Parts used:
Air filter: regular fram filter
Plug wires: NGK
Plugs: Bosch 8104 Double Platinum
I see that many recommend only using the AC Delco plugs so that may be the issue. Other than that, I did not check the gaps on the plugs when I installed them. I assumed they were at the right .40 as the box says and threw them in. I guess I should check that. Next I will replace the fuel filter becuase I am quite sure it has not been replaced in 60,000 miles.
03 'hoe 5.3 flex...
Decided to do some routine maintenance on the beast - plugs, wires, air filter - and afterwards the engine is running like crap, most notably at idle. On the highway the truck seems to have power and is smooth...at idle the engine runs slightly lumpy and, listening to the exhaust, it is obvious that there is a misfire.
I hooked up my scanner and go the reliable p0300 code but that does not tell me much. I cannot see it being the intake manifold gasket because I've changed that and because I tested it by spraying carb cleaner around the engine with no change; it doesn't seem like there is a vacuum leak at all. The live data on the scanner shows a defective O2 sensor on B1S2 (pegged at about 835mv). The other sensors seem fine though B2S2 seems a bit sluggish. The fuel trims are slightly negative ~ -3.5 on average. Would a -3.5 stft really cause a noticeable issue?
The engine seemed to run fine with the old plugs, single Platinum NGK plugs that were in it. I changed them because they were old and the center electrode was essentially gone on all of them. I changed the plug wires because some of them ripped when I removed them.
Parts used:
Air filter: regular fram filter
Plug wires: NGK
Plugs: Bosch 8104 Double Platinum
I see that many recommend only using the AC Delco plugs so that may be the issue. Other than that, I did not check the gaps on the plugs when I installed them. I assumed they were at the right .40 as the box says and threw them in. I guess I should check that. Next I will replace the fuel filter becuase I am quite sure it has not been replaced in 60,000 miles.
