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real rough idle, boost spike

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Old Dec 21, 2003 | 08:43 PM
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highspeeddubbin's Avatar
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real rough idle, boost spike

after going through about 2 hours worth of searches, i decided to just post my situation.

i was driving home from boston today with a few friends. i was in 4th gear about 5k rpm and i punched it. everything seemed fine, boost spiked a bit hit .90 bar on the avc-r which seemed strange since i have my boost set to .70 so i let of, cruised for about 10 more miles with no problems. until i got off the highway.

when i got off, we stopped to drop off a few friends. i noticed my idle was real rough. still at around 900 rms and holding but rough, i could feel it in the shifter. i parked it for an hour or so, started right up, but the weird idle is still there. still builds boost, vacume is around 12. as soon as i give it a bit of thottle it seems fine. i checked my map sensor and hoses all seem good, cars running normal temp, so im baffled.

mods. dp mp racing beat exhaust, power fc, intake, running non seq. apexi avc-r, new street ported motor w/ 12k miles,

also i pulled a vacume line off the intake manifold and that seemed to stop the shaking of the manifild, i dont know if this helps anyone but worth a shot
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Old Dec 22, 2003 | 05:21 AM
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TTT
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Old Dec 22, 2003 | 11:54 AM
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Just a long shot but check your motor mounts.
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Old Dec 22, 2003 | 03:28 PM
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mounts seem fine, thanks for the idea though
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Old Dec 23, 2003 | 05:26 AM
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??? no ideas
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Old Dec 23, 2003 | 06:25 AM
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Possibly a coil or plug wire? How old are your wires? Do you have a friend with a fresh set you could try? How old are your coils? Just a long shot!
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Old Dec 23, 2003 | 07:57 AM
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id say it has something to do with ur port, did you get ur pfc retuned after you had broken your engine in? that may have something to do with it
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Old Dec 23, 2003 | 10:44 AM
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If your engine is loping at idle (flub, flub-flub, flub-flub), then you have probably blown an apex seal. You probably had a boost spike that the seals didn't like. Hope I'm wrong. A compression test will tell for sure.
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Old Dec 23, 2003 | 10:48 AM
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Try a comp. test. You may have broke an apex seal.
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Old Dec 23, 2003 | 03:36 PM
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i have a compression test in the works, the wires look old, not sure how old, i know the plugs have been fouled a few times. i have a new set of wires im going to throw on but im going to wait until after the holidays.

thanks alot for all the response
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Old Dec 23, 2003 | 04:18 PM
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so is your vaccum always at 12 now or was it just that one time?
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Old Dec 23, 2003 | 09:11 PM
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to tell you the truth i cant really remember. i was told that if the seal was blown, the vaccum would flicker.
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Old Dec 27, 2003 | 06:45 PM
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changed plugs and wires today, still no luck, what are some signs of a blown motor.
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