New to me 2004 GTO with MAF issues
02-23-2016, 04:54 PM
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New to me 2004 GTO with MAF issues Car only has 68k miles.
The full background -
Original owner said he parked it in ~2011, and I picked it Nov, 2015. I assume it was started and driven occasionally/semi-rarely, but idk. It could have just been sitting for 4-5 years.
Everything is pretty corroded. Rotors pitted pretty badly, undercarriage.
As to be expected, the car was throwing several codes. Back in November (I THINK) it was throwing the P0300 code. I left it alone for a while as we got a bunch of snow.
I start working on it again. Driving it a bit, the fuel pump goes out. I replace the fuel pump, and realize the pump had [likely] failed due to rusty water/old gas sludge. The tank had that familiar old gas/rusty water smell, but the tank didn't look too awful.
I admit --> this is where I might have messed up. I didn't drain or replace the tank. I just replaced the pump and thought it would be good enough if I just constantly kept the tank full of new gas to get the old junk out.
Then I find out...car doesn't have inline fuel filter
Anyway, car continues to run like junk. It idles rough. RPMs don't fluctuate greatly, but it feels rough and exhaust sounds and feels like it has a miss.
Has no power. Stumbles, stalls, sputters, pops in exhaust, under any sort of load. Sometimes barely stays running.
I buy a new battery and all the problems get 60% better.
Car is now drivable, but still can't accelerate past 30% throttle.
Codes are driving me nuts. At this point, it can't make up its mind. First, it throws lean codes. Then it throws low voltage codes for O2 sensors, MAF sensor, and throttle position sensor. I reset TPS and IACV (via unplugging, then turning car on for 10 sec). Car runs a lot better now. Has power to ~60% throttle and pulls decently well until it warms up.
Car still throws codes and stalls, sputters, pops in exhaust, etc etc. Also, still idles rough, but spot on at ~520rpm.
I've cleaned MAF twice back in Nov., btw. Took it out, sprayed THOROUGHLY with MAF cleaner for 30-45 seconds in spurts.
After I reset TPS and IACV, it gives new, different codes once again. Currently, it's down to P0101 (MAF low voltage) and P0174 (lean bank 2).
Checked fuel pressure - it's 35psi with car off, key on. Jumps to 68psi at idle.
Concluded I had ground issues. Tried my best to find grounds in engine bay. I was able to find 4 grounds (under fuse box, behind battery, front of pass. side head, and ground on A/C compressor
The full background -
Original owner said he parked it in ~2011, and I picked it Nov, 2015. I assume it was started and driven occasionally/semi-rarely, but idk. It could have just been sitting for 4-5 years.
Everything is pretty corroded. Rotors pitted pretty badly, undercarriage.
As to be expected, the car was throwing several codes. Back in November (I THINK) it was throwing the P0300 code. I left it alone for a while as we got a bunch of snow.
I start working on it again. Driving it a bit, the fuel pump goes out. I replace the fuel pump, and realize the pump had [likely] failed due to rusty water/old gas sludge. The tank had that familiar old gas/rusty water smell, but the tank didn't look too awful.
I admit --> this is where I might have messed up. I didn't drain or replace the tank. I just replaced the pump and thought it would be good enough if I just constantly kept the tank full of new gas to get the old junk out.
Then I find out...car doesn't have inline fuel filter
Anyway, car continues to run like junk. It idles rough. RPMs don't fluctuate greatly, but it feels rough and exhaust sounds and feels like it has a miss.
Has no power. Stumbles, stalls, sputters, pops in exhaust, under any sort of load. Sometimes barely stays running.
I buy a new battery and all the problems get 60% better.
Car is now drivable, but still can't accelerate past 30% throttle.
Codes are driving me nuts. At this point, it can't make up its mind. First, it throws lean codes. Then it throws low voltage codes for O2 sensors, MAF sensor, and throttle position sensor. I reset TPS and IACV (via unplugging, then turning car on for 10 sec). Car runs a lot better now. Has power to ~60% throttle and pulls decently well until it warms up.
Car still throws codes and stalls, sputters, pops in exhaust, etc etc. Also, still idles rough, but spot on at ~520rpm.
I've cleaned MAF twice back in Nov., btw. Took it out, sprayed THOROUGHLY with MAF cleaner for 30-45 seconds in spurts.
After I reset TPS and IACV, it gives new, different codes once again. Currently, it's down to P0101 (MAF low voltage) and P0174 (lean bank 2).
Checked fuel pressure - it's 35psi with car off, key on. Jumps to 68psi at idle.
Concluded I had ground issues. Tried my best to find grounds in engine bay. I was able to find 4 grounds (under fuse box, behind battery, front of pass. side head, and ground on A/C compressor
02-23-2016, 04:56 PM
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Currently my thoughts are
- Borrow/buy new MAF sensor
- Check resistence for O2 sensors, but don't know values
- Check and observe cat and exhaust
- Find and clean more grounds or just run a new one