Help: Rough Idle and dip in RPMs off start
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lukegoode8
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Hey guys, just had a issue flare up on my 944s. When I start it, it dips sharply in RPMs around and below ~600 before it evens out. It also could possibly be ticking louder than usual for this car with it possibly misfiring while it bounces around 900-1000 RPMs. First time it completely died off start and I had to try again. I just replaced the distributor cap and rotor along with the plugs, but touched nothing else. I don't think it has anything to do with that though. Belts all are tight and fine, didn't blow the engine, battery is fairly new. I'm not sure where else to dig. Would love to hear some thoughts.
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Tom
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Maybe post a video. What plugs did you use, and are you sure you got the firing order right when reinstalling the wires?
Assuming that all checks out, I'd suspect a vacuum leak. Any chance you knocked something loose when changing the ignition parts -- FPR vacuum line, etc.? If you spray starter fluid around the vacuum fittings, you'd notice a change in the motor if the starter fluid gets sucked in anywhere.
Assuming that all checks out, I'd suspect a vacuum leak. Any chance you knocked something loose when changing the ignition parts -- FPR vacuum line, etc.? If you spray starter fluid around the vacuum fittings, you'd notice a change in the motor if the starter fluid gets sucked in anywhere.
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lukegoode8
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I used the Bosch OEM equivalents and gapped them correctly and the wires are correct. I don't think I knocked anything loose.
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usury
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It the spark plug wires aren't fully seated, either at the distributor or at the plug, it would probably run weird.
Freelance New Age Renaissance Man
and Wrench Warrior
1987 944na with S2/Turbo facelift
Seattle, Washington, USA
and Wrench Warrior
1987 944na with S2/Turbo facelift
Seattle, Washington, USA
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lukegoode8
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All of them seen to be seated okay, I'm fighting the idea of the ignition coil being the culprit. Could that cause all that?
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lukegoode8
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Nope, seemed to work itself out somehow. It isn't a perfect start up every time but always gets going so I'm not gonna touch it.
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lukegoode8
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That's funny I was just thinking about replacing mine because of the same thing. That makes me more confident in it then.notny41 wrote: Wed Nov 01, 2023 9:09 pm i had a strange problem where my car would hiccup and almost stall every so often at idle. i tried many many different things. finally got it fixed - my throttle pos sensor was bad.
unfortunately they aren’t exactly cheap. i found a new one on ebay for my turbo at a decent price and ever since I put it on, it’s been great.
mine used to also start difficult (mostly after it was warm). i replaced the fuel pump check valve too and all has been good since.
mine used to also start difficult (mostly after it was warm). i replaced the fuel pump check valve too and all has been good since.