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missfire under boost

B

blowngp3

New member
i started to get a missfire as soon as i hit boost a few days ago. i changed the plugs thinkin that was the cause nope. then i changed the wires and still was doing it so i got new coil packs and it still happens. any ideas on what could be causing this?
 


Can you give some specifics about the car, whens it happens and how does the car react? How do you know about the misfire? Codes?
 
Either your O2 sensor is bad or you have a clogged cat. If you have a boost guage monitor it to see if your boost is higher than normal. If so your cat is clogged. Are u throwing any codes?
 
its an 01 with 3.4, ported exhaust manifolds, 3" catless dp, and dhp 1.0 the check engine light is on because my rear o2 sim went bad. as soon as i hit boost the car starts to studder. i replaced my front o2 less than a year ago.
 
Unplug the BBV and see if it still misfires at higher rpm's. This restricts the boost to 3-5psi. Just start with that and see what you can work to eliminate the problem to.
 


make sure your mass air flow sensor isnt sh**ting the bed. mine did that just a little bit ago. mine was doing the saime kind of thing. its from the engine leaning out cause its thinking its getting more air than gas.
 
Ok so i am having this exact problem I unplugged my BBV and the problem barely exists..So what does that mean new BBV? Vacuum lines? Spark plug gap? I heard of someone similar dropping the gab from .60 to .45 and fixed the problem Im going to try that soon today will let you know.
 
more than likly i havd the same problem, at idle the bbv flap shud b upward and when its accelrated it should close hope this helps.
 
Take the metal spark plug boot retainers off. I had this exact same problem, It ran great normally but when I got into boost it misfired. That is what it was. Those stupid metal things
 


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