Engine having hick-ups at low speed
10-05-2006, 12:57 PM
#1
Track Day
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Engine having hick-ups at low speed
Hello, since 6 months I own a 964 C4 of 1991 and it has a problem nobody could fix yet.
Running the car a low revs sometimes it will not run smoothly but with hick-ups and also during the accelleration it runs bad, when stopping the engine will not keep idle and stalls. The real problem is that the car doesn't always have the problem and sometimes runs perfectly for hundereds of Km's.
The car was checked by 2 porsche dealers but they couldn't locate the problem, all the ignition cables were changed but this made no difference....
Any idea what could cause this problem? All ideas will be more than welcome!
Marco (Italy)
Running the car a low revs sometimes it will not run smoothly but with hick-ups and also during the accelleration it runs bad, when stopping the engine will not keep idle and stalls. The real problem is that the car doesn't always have the problem and sometimes runs perfectly for hundereds of Km's.
The car was checked by 2 porsche dealers but they couldn't locate the problem, all the ignition cables were changed but this made no difference....
Any idea what could cause this problem? All ideas will be more than welcome!
Marco (Italy)
10-05-2006, 01:03 PM
#2
Nordschleife Master
Hiya MMartini
I would love to see the car in person .
Do you work on cars ? Are you comfortable / happy to work on your own car ?
Where in Italy ?
If I help you fix it , can I drive it around Italy ?
I would love to see the car in person .
Do you work on cars ? Are you comfortable / happy to work on your own car ?
Where in Italy ?
If I help you fix it , can I drive it around Italy ?
10-05-2006, 01:17 PM
#3
Track Day
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I didn't work much on my new toy yet but am quite happy to work on it.....
I'm living at lake Como in the north of Italy, real nice area to cruise.
I'm living at lake Como in the north of Italy, real nice area to cruise.
10-05-2006, 01:31 PM
#4
Nordschleife Master
Ok then , time to look at all the parts that make up the ignition system . Caps , rotors , coils .
Have you had them out for a good look see ?
Do you know how many miles / kilometers or years old , the caps , rotors or coils ?
So if I help you fix it , do I get to drive it around lake Como ?
Have you had them out for a good look see ?
Do you know how many miles / kilometers or years old , the caps , rotors or coils ?
So if I help you fix it , do I get to drive it around lake Como ?
10-05-2006, 01:45 PM
#6
Rennlist Member
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Sounds like the Airflow Meter Wiring Harness issue. There is a TSB for that. Seems like there was a recent thread here somewhere. If you search AFM Harness, I bet you will find it.
Its an easy fix, BTW, although of course it may NOT be your problem.
Brian
Its an easy fix, BTW, although of course it may NOT be your problem.
Brian
10-05-2006, 01:48 PM
#7
David you crack me up!
If you find your way out to New York you're more than welcome to dive my car!! I'm near the Catskills and out in the country and not far from the Big Apple; North, West or East, take your pick. South is New Jersey. No offense, but not much fun to drive that way.
If you find your way out to New York you're more than welcome to dive my car!! I'm near the Catskills and out in the country and not far from the Big Apple; North, West or East, take your pick. South is New Jersey. No offense, but not much fun to drive that way.
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10-05-2006, 01:50 PM
#8
10-05-2006, 05:38 PM
#9
Track Day
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Thanks for the ideas, I had a look at the Airflow Meter Wiring Harness problem description and it looks very similar to the problem, it also sometimes seems to happen on bumpy roads. Rain doesn't have any effect on the problem.
The TSB states that it only happens on 1989 and 1990 models, mine is a 1991 (M)..... could the Airflow Meter Wiring Harness still be the problem?
Thanks Marco.
The TSB states that it only happens on 1989 and 1990 models, mine is a 1991 (M)..... could the Airflow Meter Wiring Harness still be the problem?
Thanks Marco.
10-06-2006, 07:54 AM
#11
Addict
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There is a filter screen for the fuel suction inside the gas tank. It can clog, and problems can be intermittent. It may not be the problem, but it is easy and cheap to pull it out and clean it. You might be surprise at how much muck accumulates at the bottom of a fuel tank in 16 years.
10-06-2006, 08:34 AM
#12
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In addition to all the above, do get your wiring checked. Mine had similar problems of low idle, misfiring but sometimes OK. After 2 garages and many hours, they found a wire was shorting and fooling the mixture sensors. Now its fine. See my thread: https://rennlist.com/forums/964-turbo-forum/294138-uneven-idle-is-this-a-problem.html
10-06-2006, 10:12 AM
#13
Originally Posted by springer3
There is a filter screen for the fuel suction inside the gas tank. It can clog, and problems can be intermittent.
Is it difficult to get to? Do you have to drain the tank and come in from below?
Thanks,
Dave
10-06-2006, 07:10 PM
#15
Burning Brakes
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I checked my screen as one of the steps to diagnosing my ongoing problem Dave. It wasnt really too bad of a job, and my screen was clear. Wish I had one of those snake cameras to look in there before doing all that work.