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MAF Readings 05 Grand Prix

indygrandprix

indygrandprix

New member
Got a trouble code for cylinder 3 misfire a few days ago. Swapped the coil pack out with one from my 01 GP but still had the same issue and now it has gone from just cylinder 3 misfire to a random multiple cylinder misfire. Thought maybe it was the MAF as the car stumbles under semi hard to hard acceleration and has a hard time keeping speed and sorta bogs on the highway. Tested the MAF and it has voltage but the Hz readings are off compared to what my research indicated they should be.

I got 2.7 @ 750RPM(Idle), 3.4@ 1500RPM and 4.1@ 2500 RPM

My research indicated I should have 3.2 @680 RPM(Idle), 4.2@1500RPM, and 5.2@2500 RPM

From what I read it's more important that the readings increase smoothly than what they are but I'm not sure if thats true. So is my MAF sensor bad? I did clean it which made the readings a tiny bit higher. The readings I posted here are what I got after the cleaning.

Also at ~3500 rpm I got about 4.9Hz but I couldn't find a spec for that RPM

If it's not the MAF what would the next thing to look at be. Ignition Module? I have no other codes.
 


Well you aren't reading Hz thats for sure, they are on a scale on 0-11,500. So you must be reading something else like volts but I don't really know.

MAF readings are not the same for everyone because there are many variables here like air density, altitude, air temp and so on that change the readings from the MAF sensor.
 
if it's the maf sensor, you should be able to unplug it without the engine running, and then start the car and it should run better. just don't plug it back in until the car is off.
 
I just did the plugs, wires, air filter and cleaned the tb a few weeks ago.

The numbers I posted are thousand Hz so 2.7 would be 2.7K 3.2 would be 3.2K ect

Unplugging it seems to make it run crappy at dead stop or low speed acceleration but it seems better if you mat the gas at 30mph or so.

I also checked the fuel psi. It stays at ~60psi throughout the rpms
 
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fuel pressure should be right at 65 psi and doesn't change while operating. Do you still have the little metal sheilds around the plug boots?
 


when the maf is disabled, the car falls back onto a speed density tune, which doesn't adjust for fueling changes like the car should with the maf sensor, so it's not going to run as good, but if you mashed the pedal and it's not doing what it was previously doing, it seems like it would be the maf sensor that has failed.
 
My 05' flips it's **** if I unplug the MAF. It'll go into reduced power if I nail it. That may be a GTP thing though. When you unplug the MAF you also lose IAT as well.

Jeff
 
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