Cutting out, surging, check engine light...

Discussion in 'Fox 5.0 Mustang Tech' started by 90mustangGT, Dec 8, 2003.


  1. 90mustangGT

    90mustangGT I felt sorry for girls because Founding Member

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    These are problems I have had and just can't quite figure them out:

    1. Sometimes when I put the petal down quickly, it just cuts out dead, kind of like someone just cut the ignition off and when I let off it just runs normally. The FP stays at 40psi (autometer FP gauge) but I am wondering if this is a sign of a bad module, coil, or worse yet computer which are all original to my knowlege.

    2. When on the highway in 5th gear, if I give it WOT, it seems to have inconsistant power. Instead of a steady constant pull it seems to pull but a surging pull, hard to explain, follow me???

    3. It surges when it is first started warm, give it a rev and it quits. Positioning the idle up a little helped alot but it still does this sometimes. TPS set to .997

    4. When the engine is below 180* at partial throttle the check engine light will come on, it will go off by putting the throttle down 1/2 or more, or letting off. Not really a problem but kind of makes me wonder.

    I have stock FP, FPR, and injectors, the A/F ratio meter reads rich to the rev limiter, and the FP stays constant at 40psi.

    I have pulled codes. I got a thermactor code, a insufficient EGR flow, and a low MAF voltage, I can't remember, I think it was out voltage, but it could have been input voltage. I think this might be the problem. Would this mean I have a bad MAF sensor itself or does it have to do with the C&L housing?

    Any help or experince with these problems and how you fixed them would be apreciated. Thanks in advance...

    -Jason
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  2. nito88stang

    nito88stang Founding Member

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    The engine diagnostics does not know of the housing. It would most likely be consistent with a bad MAF sensor itself. At first upon reading your initial writing i was sure it woudl be a TPS because of the sudden cuttin out upon stabbing the throttle. But a MAF is certainly capable of doing that also. Swap it out with a buddies and see if that is the culprit before buying one though.

    A bad module or TFI would give you crap once the engine is warm and running for a while. Trust me, going on the freeway then having ur car die while ur in the fast lane is no fun, been there. So you can rule those out if you're having trouble at cold engine. Same thing with fuel pump.
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  3. 90mustangGT

    90mustangGT I felt sorry for girls because Founding Member

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    Your right, the Snap On scanner has no clue what I have done to the engine, lol. I work in a shop as a Technitian's Assistant and see all kinds of problems and usually my kind of problem is either a faulty MAF, fuel pump, or a TPS. Thanks...
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  4. Blandnuts

    Blandnuts I don't swallow; I only swoosh Founding Member

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    I had the EGR one too and the light would come on and off occasionally. I took off the EGR and cleaned it out and the wires that led to it and didn't have a problem for a few days. Later the light popped back on then went off. Did that for a few days. A month later now I haven't had the check engine light pop on once...


    I'd do what nito88stang says and try using a buddies MAF sensor and see what that does.



    fred
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  5. 90mustangGT

    90mustangGT I felt sorry for girls because Founding Member

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    I think if it was the EGR it would also go on at idle. Only at partial throtle. I swear, I am tempted do go carbed, enough with this electronic BS.
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