Sandman3175
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- May 12, 2014
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Hey guys...hopefully someone can help me out here.
I have a 2001 Tahoe 5.3L 2wd with 250,000 miles (all original). I've had this car for 11years and have done all your normal maintenance religiously. I've never had any major problem until recently (except for your normal failed alternator, water pump, etc.) and can't seem to figure this out.
Several weeks ago I started experiencing rough idle, loss of power, bad fuel mileage, etc...your typical misfire problems. CEL came on and started flashing. At first it only did it every now and then but now it has gotten to where it does it almost daily.
It seems to always start misfiring around the same time (approx 5-10 minutes) after the car starts....not sure if this is a coincidence or when the engine warms up. Sometimes after driving it like this it will "fix" itself and drive normal again and CEL goes out. If it's misfiring and I turn the car off for a few minutes this will sometimes fix the issue (but not always). Also, here recently Im constantly adding coolant with no visible leaks on or under engine (thinking intake manifold gasket failure). I've also noticed that when the low coolant light comes on the car will start acting up almost every time
So now to the repairs...
I pulled into a parts store and got the following codes: P0300, P0332, P0171, P0174, P1571.
Trying to troubleshoot this random misfire and fuel issue, over several weeks I went ahead and put on new coils, AC Delco plugs, wires, Delphi knock sensors (w/RTV dam) and new knock sensor harness. I took off and cleaned the intake manifold and cylinders and replaced with new Felpro gaskets (hoping this fixes the coolant leak). I cleaned the terribly dirty fuel injectors. Cleaned out the throttle body and replaced gasket. Cleaned the MAF sensor with MAF cleaner. Cleaned and inspected the EGR valve (seems to be good) and replaced gaskets. Replaced the fuel filter just because. Replaced the PCV. Still getting the same random misfire as stated above but the car does have a lot more power now.
Two days ago it was acting up and I was right in front of O'Reilly's so I pulled in to have the codes read. The guy didn't give me the codes but I do know there was a P0304 (first time it signaled a single cylinder) code and three codes that had to do with the throttle position sensor. Since it was fairly inexpensive I went ahead and bought a new one. Of course he gave me the wrong one (w/o traction control). I asked him if he could clear the codes but said that company policy says he can't and didn't. Got home and inspected around cylinder four and swapped out cylinder two and cylinder four coils to see if maybe it was the coil. Car still misfiring and throwing CEL. I tried the old 'disconnect your battery to clear the codes trick' and CEL goes out.
Yesterday, I go to a different O'reilly's to get the correct TPS sensor and had them reread the codes since the CEL came back on (and to see if cylinder two was misfiring now).
This time I got the following codes: P1120, P1220, P1516 & P1518 (new to me?) and P300. I asked again if they could clear the codes and he said no but that I could use the tool and do it, which I did.
Hoping the new TPS would take care of most of these codes, I got home and replaced it. All seems good (no lights, seemed to be running good for half the day) but of course she starts misfiring again. Pulled into Autozone since I was close by to have the codes read again (same day) just out of curiosity.
Now I get the following codes: C0221, C0223, C0227, C0265, C0287, C0298, P0300 and P1638. Both front hubs w/new abs sensors installed approx 6-8 months ago, alternator replaced approx 1yr ago. Since being replaced I haven't had any problems with either.
I am at a loss. I'm thinking PCM? Why else would I be getting so many random codes? Would a bad MAF or EGR create any/all of these codes?
Any help is appreciated.
I have a 2001 Tahoe 5.3L 2wd with 250,000 miles (all original). I've had this car for 11years and have done all your normal maintenance religiously. I've never had any major problem until recently (except for your normal failed alternator, water pump, etc.) and can't seem to figure this out.
Several weeks ago I started experiencing rough idle, loss of power, bad fuel mileage, etc...your typical misfire problems. CEL came on and started flashing. At first it only did it every now and then but now it has gotten to where it does it almost daily.
It seems to always start misfiring around the same time (approx 5-10 minutes) after the car starts....not sure if this is a coincidence or when the engine warms up. Sometimes after driving it like this it will "fix" itself and drive normal again and CEL goes out. If it's misfiring and I turn the car off for a few minutes this will sometimes fix the issue (but not always). Also, here recently Im constantly adding coolant with no visible leaks on or under engine (thinking intake manifold gasket failure). I've also noticed that when the low coolant light comes on the car will start acting up almost every time
So now to the repairs...
I pulled into a parts store and got the following codes: P0300, P0332, P0171, P0174, P1571.
Trying to troubleshoot this random misfire and fuel issue, over several weeks I went ahead and put on new coils, AC Delco plugs, wires, Delphi knock sensors (w/RTV dam) and new knock sensor harness. I took off and cleaned the intake manifold and cylinders and replaced with new Felpro gaskets (hoping this fixes the coolant leak). I cleaned the terribly dirty fuel injectors. Cleaned out the throttle body and replaced gasket. Cleaned the MAF sensor with MAF cleaner. Cleaned and inspected the EGR valve (seems to be good) and replaced gaskets. Replaced the fuel filter just because. Replaced the PCV. Still getting the same random misfire as stated above but the car does have a lot more power now.
Two days ago it was acting up and I was right in front of O'Reilly's so I pulled in to have the codes read. The guy didn't give me the codes but I do know there was a P0304 (first time it signaled a single cylinder) code and three codes that had to do with the throttle position sensor. Since it was fairly inexpensive I went ahead and bought a new one. Of course he gave me the wrong one (w/o traction control). I asked him if he could clear the codes but said that company policy says he can't and didn't. Got home and inspected around cylinder four and swapped out cylinder two and cylinder four coils to see if maybe it was the coil. Car still misfiring and throwing CEL. I tried the old 'disconnect your battery to clear the codes trick' and CEL goes out.
Yesterday, I go to a different O'reilly's to get the correct TPS sensor and had them reread the codes since the CEL came back on (and to see if cylinder two was misfiring now).
This time I got the following codes: P1120, P1220, P1516 & P1518 (new to me?) and P300. I asked again if they could clear the codes and he said no but that I could use the tool and do it, which I did.
Hoping the new TPS would take care of most of these codes, I got home and replaced it. All seems good (no lights, seemed to be running good for half the day) but of course she starts misfiring again. Pulled into Autozone since I was close by to have the codes read again (same day) just out of curiosity.
Now I get the following codes: C0221, C0223, C0227, C0265, C0287, C0298, P0300 and P1638. Both front hubs w/new abs sensors installed approx 6-8 months ago, alternator replaced approx 1yr ago. Since being replaced I haven't had any problems with either.
I am at a loss. I'm thinking PCM? Why else would I be getting so many random codes? Would a bad MAF or EGR create any/all of these codes?
Any help is appreciated.
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