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Engine trouble, help needed

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Old 06-02-2005, 05:09 PM
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Default Engine trouble, help needed

I really hope someone can give me some idea of what is going on with my car. It is a 99 z28 m6.

Here is the story, the car hesitates under throttle pretty noticably, My dad had a MAF from a Z06 which we thought would fit just to try a new part. We put it in and plugged it in, the car ran great, however later we realized that it was the wrong part and all we really accomplished was running the car with no MAF. It immediatly threw a SES light. I thought a bad MAF would make the car run goofy . so I ordered a new SLP (The right one) I hooked it up today, reset the computer and the problem is still there, although maybe a tad less noticable. I have no clue what could be wrong. The plugs are fine, some people have mentioned o2 sensors however i dont have $300 to "test" if that is what the problem is. The car isnt throwing any codes so I am really walking in the dark.
Old 06-02-2005, 11:17 PM
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Seems like usually the O2 sensors are real quick to throw codes if there's something wrong with them, so I'd guess it's something else...?
Old 06-03-2005, 02:17 AM
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This could be any number of things. How many miles does it have? Does it stumble under a load or even at park?. Could possibly be a fuel issue or a vacuum leak somewhere.
Old 06-08-2005, 11:47 PM
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crOy~

Sounds like we have the same problem. I have a 99 formula firehawk and i started getting the "hesitation" a couple months ago. Just recently took it to the dealership to have it checked out. They were clueless since the car never through a light (you'd think they'd know these engines) so they started checkin by trial and error. I'll get to the point, after ruling out the fuel pump and O2 sensors, they tried and injector flush. Didn't fix the problem but runs a little better, stressing little, 300 bucks later, what a rip. They said the next things to try would be changing out the MAF, and next computer error.

If anyone has a clue to the problem or knows the fix i'd appreciate the info.
Old 06-09-2005, 07:49 AM
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is the hesitation the same throughout all gears and rpm ranges? is there a rough idle? if you could be a little more specific i can try to give my best answer.
Old 06-09-2005, 04:04 PM
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A majority of the time the hesitation is around the 2200 rpm range for me, although sometimes it happens at around 3000 and 1500. It only noticeable through gears 2-5, although it could be happening throughtout them all. The idle is fine. When you go hard through the gears, or drive real easy it doesn't seem to do it or its not noticable, its only with mild to average acceleration that I can feel it.

Thnx for any help
Old 06-09-2005, 06:24 PM
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i have the same problem, hesitation like hitting a limiter, feels like it dies until get thru it's rpm range of hesitation which would be around 2500 to 3k and even then it doesn't feel like it's as powerful going beyond 3k, still seem like something is happening, i've changed out my spark plug wires i thought it was good to go. until it just came ack again, and i noticed sometimes it's there other times it's not but for the most part it's there. i'm going to be doing my spark plugs and fuel filter next see if that helps. even try'd messing with my tune with spark, but it just moved it higher in the rpm range.. but whats weird is its at the same spot everytime.. and my intake monifold gaskets are new also. i was thinking maybe my MAF has gone bad or something. but it happens on all loads just the more you accellerate the faster it goes thru the hesitation,, but still being pressent..
Old 06-14-2005, 03:01 AM
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well i deleted the MAF and did a MAFLess Tune problem still exist, it pretty much seem to be just the entire power band. more noticable in other areas. so changed my oil and put new spark plugs in.. car felt better and had more power, needed a spark plug change badly, but problem still exist... I'm not throwing an codes Either. now i'm thinking some in the tune but nothing was ever changed and it just suddenly happened, next i'm thinking i have no clue. CAM sensor maybe good thing is i have 2 extra to try out. but the time i dont. what to do
Old 07-25-2005, 11:57 AM
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bent pushrod?




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