Horrible studder/misfire
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Mountain Pass
Joined: Feb 2011
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Horrible studder/misfire
98 Expy, 5.4,no codes.
I have a horrible misfire at arouond 1500rpm.
If I press the gas and hold it to 1500rpm,the engine will shake and drop to about 1200rpm then back up to 1500 and so on all while keeping the pedal at the same spot.
Am I do for a tune up/coil change? Bad TPS? IAC bad?
I have a horrible misfire at arouond 1500rpm.
If I press the gas and hold it to 1500rpm,the engine will shake and drop to about 1200rpm then back up to 1500 and so on all while keeping the pedal at the same spot.
Am I do for a tune up/coil change? Bad TPS? IAC bad?
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Mountain Pass
Joined: Feb 2011
Posts: 145
Likes: 0
It does it in park and while driving, basically anytime it hits 1500rpm.
I will try the egr trick tomorrow.
Senior User
Joined: Sep 2011
Posts: 448
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In park or neutral, The test is your checking to see if the egr spring in the valve is weak in general acceleration, most noticeable in park or neutral if your slowly bring the rpms up between 1000 and 2000 the pcm does a check on the egr system, its tells the evr to send about 3 to 3.5 ingh of vacuum to the egr to open slightly, when the egr valve spring is weak the valve will open too far and cause a stumble until the pcm detects this and corrects it, you can see this if you tee in a vacuum gauge at the egr
This might be your issue.
This might be your issue.
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bduke23
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