fightingpenguinz

Hey all,

I have an 89 GT with a 347 stroker and 24lb injectors, Pro-M calibrated MAF for 24lbs. The car was running great after I got the MAF about 10 months ago. I've been having this issue for the past couple months, although it doesn't happen all the time. I will be cruising in 4th, lets say, and all of a sudden I will lose power from the motor, it doesn't stall, but RPMs drop to less than idle and I have no response when I press the pedal, then all of a sudden power comes back and the car lunges. I first thought it was ignition but now I'm starting to think its the fuel pump.

Since then I have:
-Done a tune-up less than a year ago (plugs, wires, cap, rotor)
-Cleaned the 10-pin connectors and removed their extension harness
-New distributor with ignition module and hall effect
-New O2 sensors
-New fuel filter

The problem can range from a quick sputter while driving, to not being able to get down the road. Car always starts, too.

Throws codes 31 ( EGR Valve Position/Pressure Feedback EGR Circuit Below Minimum Voltage. 0.24 volts (O,M,R) ) and code 66 (MAF signal below minimum test voltage of .4vdc (O,M,R) ).

Are the calibrated MAFs known to throw code 66? Could a bad MAF actually cause this type of power loss? Or should I go ahead and get a new fuel pump with a pressure regulator?

Thanks.

AdderMk2

bad maf can, and WILL cause that.

get a lightning 90mm MAF nd some 30# injectors... then get a tune.

fightingpenguinz

Thanks for the reply. I could put my stock MAF back on and see if the problem disappears. I have talked to my local performance shop, and he seemed reluctant to even put my build on the dyno and recommended the calibrated MAF. It's my daily driver so I'm really just after fixing the problem for now. I'll report back.

BBK Longtubes
BBK Off-road H-pipe
Crane Cam
Cobra Intake, 70mm throttle body
GT-40 heads

AdderMk2

Your car would max the stock MAF. You need something bigger... like an LMAF.

P.S. Your h/c/i sucks...

fightingpenguinz

I know, its a terd, 347 with bolt-on 302 parts, I hope to change that in the future. Just trying to make the car reliable for now.

AdderMk2

well, start by getting rid of the piece of **** MAF, and get some slightly lager injectors.

fightingpenguinz

Just measured the voltages on the Pro-M MAF, I have 0.067V on the return at idle...but it idles good. Gonna ride with the stock MAF for a week and see if the problem still occurs. The part is less than a year old and I bought it off of MustangsUnlimited.com, should I expect any kind of return or exchange from them or Pro-M? Thanks.

AdderMk2

not with those injectors you arent...