( I just wanted to share this with you guys because it took me forever to figure it out. If you have anything to add to this feel free to post)
If your car has been running like crap and you can't figure it out, read this and see if this matches your symptoms. My car ran like crap for months and I couldn't figure it out. And my brother-inlaw that is a mechanic found this on his computer at work.
I read it and match mine almost to the tooth.
I didn't get all the codes but, I had a lot of the symptoms.
The way I tested my MAF was that I unplugged it (your car will not idle and will run like funky) But just find somewhere and floor it, and see if the driveability is better. If so try getting a new MAF, mine for my 94' GT was $55 at autozone ($60 core.) And took under 10 minutes to change. So, it is worth a try you know. My car now runs like a bat outta hell... So take a look at this:
MASS AIR FLOW (MAF) Discussion
MAF sensors can get contaminated from a variety of sources: dirt, oil, silicon, spider webs, potting compound from the sensor itself, ect. When a MAF sensor gets contaminated, it skews the transfer function such that the sensor over-estimates air flow at idle (causes the fuel system to go rich) and under-estimates air flow at high air flows (causes fuel system to go lean). This means Long Term Fuel Trims will learn (negative) corrections at idle and learn rich (positive) corrections at higher air flows.
If vehicle is driven at Wide Open Throttle (WOT) or high loads, the fuel system normally goes open loop rich to provide maximum power. If the MAF sensor is contaminated, the fuel system will actually be lean because of the under-estimated air flow. During closed loop operation. These corrections are often lead corrections learned at lower air flows. This combination of under-estimated air flow and lean fuel trim corrections can result in spark knock/detonations and lack of power concerns at (WOT) and high loads.
Symptoms
^ Lack of power
^ Spark knock/detonation
^ Buck/Jerk
^ Hesitation/Surge on acceleration
^ Malfunction Indicator Lamp (MIL) Illuminated
OBDI DTCs
^ 181, 189 (Fuel system lean, Bank 1 or 2)
^ 179, 188 (fuel system rich, Bank 1 or 2)
^ 171, 172, 173 (HO2S11 lack of switching, Bank 1)
^ 175, 176, 177 (HO2S21 lack or switching, Bank 2)
^ 184, 185 (MAF higher/ lower than expected)
^ 186, 187 (Injector pulse width higher/lower than expected)
Codes
OBDII DTCs
^ P0171, P0174 (Fuel system lean, Bank 1 or 2)
^ P0172, P0175, (Fuel system rich, Bank 1 or 2)
^ P1130, P1131, P1132 (HO2S11 lack of switching, Bank 1)
^ P1150, P1151, P1152 (HO2S21 lack of switching, Bank 2)
If your car has been running like crap and you can't figure it out, read this and see if this matches your symptoms. My car ran like crap for months and I couldn't figure it out. And my brother-inlaw that is a mechanic found this on his computer at work.
I read it and match mine almost to the tooth.
I didn't get all the codes but, I had a lot of the symptoms.
The way I tested my MAF was that I unplugged it (your car will not idle and will run like funky) But just find somewhere and floor it, and see if the driveability is better. If so try getting a new MAF, mine for my 94' GT was $55 at autozone ($60 core.) And took under 10 minutes to change. So, it is worth a try you know. My car now runs like a bat outta hell... So take a look at this:
MASS AIR FLOW (MAF) Discussion
MAF sensors can get contaminated from a variety of sources: dirt, oil, silicon, spider webs, potting compound from the sensor itself, ect. When a MAF sensor gets contaminated, it skews the transfer function such that the sensor over-estimates air flow at idle (causes the fuel system to go rich) and under-estimates air flow at high air flows (causes fuel system to go lean). This means Long Term Fuel Trims will learn (negative) corrections at idle and learn rich (positive) corrections at higher air flows.
If vehicle is driven at Wide Open Throttle (WOT) or high loads, the fuel system normally goes open loop rich to provide maximum power. If the MAF sensor is contaminated, the fuel system will actually be lean because of the under-estimated air flow. During closed loop operation. These corrections are often lead corrections learned at lower air flows. This combination of under-estimated air flow and lean fuel trim corrections can result in spark knock/detonations and lack of power concerns at (WOT) and high loads.
Symptoms
^ Lack of power
^ Spark knock/detonation
^ Buck/Jerk
^ Hesitation/Surge on acceleration
^ Malfunction Indicator Lamp (MIL) Illuminated
OBDI DTCs
^ 181, 189 (Fuel system lean, Bank 1 or 2)
^ 179, 188 (fuel system rich, Bank 1 or 2)
^ 171, 172, 173 (HO2S11 lack of switching, Bank 1)
^ 175, 176, 177 (HO2S21 lack or switching, Bank 2)
^ 184, 185 (MAF higher/ lower than expected)
^ 186, 187 (Injector pulse width higher/lower than expected)
Codes
OBDII DTCs
^ P0171, P0174 (Fuel system lean, Bank 1 or 2)
^ P0172, P0175, (Fuel system rich, Bank 1 or 2)
^ P1130, P1131, P1132 (HO2S11 lack of switching, Bank 1)
^ P1150, P1151, P1152 (HO2S21 lack of switching, Bank 2)
