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Well im having a bit of problems with my engine, some of the times when i accelarate, as the engine revs, and it get between the 2000-2500 rev range it sttuters (just stays there like there was a limiter) and one or two seconds later if continues to rev,


it makes like a farting sound, could it be missfire?? could it be the spark plugs???
or maybe timing??

or what else could cause the problem

also its almost always at WOT......

any help would be apreciated, thanks

 
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Have you checked the air/fuel ratio with a dyno? It may be a dip in the power band due to mods. But check the plugs to be sure.

 
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well as far as mods, all i have is 2.5 midpipe and tanabe racing medallion catback,,,,,,,,,

and there no dyno to chek it here... anyother way to check the A/F ratio??

 
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any one else would know what could be wrong??

 
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Possible knock. Check plugs, put some higher octane gas and see if it persists....any CEL's?

 
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Find a place with a wideband O2 sensor that can be hooked to your car. But I doubt it's a tuning issue. It may be that your exhaust setup is too large and is causing enough backpressure loss to make the car bog down. I only have a thermal rear section exhaust and at that same rpm range you describe, my car bogs down and the rpms drop for a few secs. Then it starts going up again. This is all with the same pressure on the gas pedal. So I think that might be the problem. I don't think there's a fix really, but maybe getting an intake would provide more air intake so it doesn't bog as much. I know with everything stock, my car never did this.

 
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How is it from a dead stop, if you try to leave hard. Does it miss, or just in the 2000-2500 range? I say the spark plugs.

 
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Ok...Gearbox I know you have been around here for a while, but A/F and timing are both tuning elements. Telling him to hook a WB A/F is a tuning issue, which is what I said. The exhaust backpressure possibility is almost totally not the cause because even when I was N/A I had a 60MM catback and never had any issues. He is talking about a hiccup or thunk, which are audible signs of knock.

Of course I lost a little low end, which is expected due to larger pipe diameter on an N/A vehicle. The 5 Zigen catback is the only exhaust I had on it N/A that gave it a stronger low and mid-range. The Tanabe's did none of the above for it.

 
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Oh sorry I didn't mean that. I was saying his problem prolly isn't from bad air/fuel ratio if it only has those few mods. Yes a/f = tuning issue. Yup it seems like either plugs or maybe try better gas to see if it goes away. Still don't remember if you said there's a CEL on.

 
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Ive had no CEL's, and i used to have a Race Header With High FLow cat, and my cat back and never had any issues...

Darisld, it hapens sometimes when the car downshifts and try to accelerate again, or when i punch it, but when the car's in neutral it does not occur...

I sold mi header and boud a midpipe for the turbo, ill check the plugs, and might change to higher octane if i keep having ploblems,

thanks Dezod and Gearbox.....