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Registered
Join Date: Jan 2010
Posts: 164
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Lots of sputtering?
Latley when i've been driving, my car likes to sputter, and and jerk below around 2k rpm, and up to around 4 sometimes. it happens at random times, but usually when it's getting warmed up. I though it might be the fuel filter, so i changed it, and it doesn't do it as much, but it still does it a decent amount.
any clue to what it could be? |
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04-25-2010, 06:04 PM
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Registered
Join Date: Jan 2010
Posts: 164
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Anyone?
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04-26-2010, 11:39 AM
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yarfk
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Have you checked the fuel pressure?
Have you checked for vacuum leaks?
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------Keith------kfray------yarfk------- 87 944 NA stock 116k 06 Honda Ridgeline 83k 10 Vibe 2.4 AWD (Wife's) Retired My week consist of Saturdays and Sundays 
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04-26-2010, 12:14 PM
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Registered
Join Date: Jan 2010
Posts: 164
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I couldn't find vacuum leaks. good pressure. i think it might be in the distributor cap. It completly quit today. in the middle of an intersection, 45 minutes from my house. But i got it running, and had to baby it all the way home or it would sputter allot
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04-26-2010, 05:45 PM
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Redline Racer
Join Date: Jan 2007
Posts: 2,444
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Does it straighten out when you hit full throttle once it starts sputtering? If it magically clears up at WOT, that narrows it down a bit. Assuming the throttle switch is working correctly, WOT puts the DME in open loop mapping off of 1 dimensional full throttle maps which disregards both the O2 sensor and the AFM signal making just basic fueling and ignition the only factors. Vacuum leaks, dirty or worn AFM, or wonky O2 sensor should not affect anything once in full throttle mode. I had the same sort of thing happen once warmed up and it completely vanished if I hit WOT. It stopped screwing up when I disconnected the O2 sensor and ran fine once I replaced it with a new one.
Does the DME temp sensor test within spec?
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1987 silver 924S made it to 225k mi! Sent to the big garage in the sky |
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04-26-2010, 06:26 PM
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Registered
Join Date: Jan 2010
Posts: 164
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That could be it, for awhile, that was the case, but i would have to ease into WOT, at about 2k i could smash it, and it would clear out.
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04-26-2010, 07:21 PM
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Automotive Necromancer
Join Date: Nov 2006
Location: Beantown, MA
Posts: 1,544
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just guessing..
My DME relay just gave up the ghost...ON it's way the car occasionally sputtered. Replace the relay or bypass it (carefully!) to see if this solves the prob. Even if it doesn't it is good to have a spare.
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There may be nothing quite as expensive as a cheap Porsche: Ruby Red 84 928S : White 87 924s 2.5L NA (Blinky) M44/07-43H10676 spoiler delete - 046/2B - Belts 9/12, Clutch and OC seals 8/08 andd Red 94 Del Sol: Please put your Make, Model and Year in Sig. Try not to break more than you fix. |
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04-27-2010, 01:51 PM
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Registered
Join Date: Sep 2001
Location: Erie, PA
Posts: 41
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Does it have a rough idle after it warms up? I just went through this. Felt like a miss through entire throttle range with light backfiring or "woofs" every couple seconds felt at the tail pipe. Always ran fine until several minutes after starting then the "sputtering" would start. Ended up being a bad injector. Diagnosed by using an infrared thermometer gun and measured the temps at the exhaust manifold ports. # 1 cylinder was consistantly running ~100 degrees cooler than the others, which narrowed down the offending cylinder. I was able to temporarily fix the injector by using a socket extension pressed against the injector then lightly tap it with a hammer while the vehicle was running. I replaced the injectors and it runs like new.
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'86 944 N/A Metallic graphite |
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04-27-2010, 07:39 PM
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Keith's Porsche
