Car randomly runs like crap

[white92talontsi]

Not sure where to post this but ill try here. Car is a 90 awd tsi. What is happening is randomly the car will start to run rough. When it does this it will idle choppy like its got big cams in it. You can let the car sit and idle choppy and then out of the blue something will clear up and the idle will jump up real fast and surge a bit. Going down the road if it does this it runs really bad. It will spit and sputter, i can clear it up by either hitting 5psi or giving it half thottle. Then sometimes it will clear up on its own and the car will take off like a rocket. This is all random. Yesterday i drove the car on a 120 mile trip with no issues. On the way back it started acting up. Also when it acts up while driving i can turn the key off while in gear and then back on and it will clear up.

Another issue is the car will randomly shut off while driving. It can go a week without doing it then out of the blue it will shut off. Its not fuel as it just dies. Tach will drop to 0 there will be no loss of power before this happens. The mpi relay is good i never hear it click when this happens. Its gote baffled. I tried another cas with no luck.

Don't know if this is related either but sometimes the doors will lock themselves while riding down the road. When i go to get in the car i unlock the doors and they lock right back too. I have to unlock the door 3 or 4 times and then it will stay unlocked.

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[khartley]

Does it act up when your fuel is around a quarter of a tank or less? Could be you got some dirty fuel, and have some particles floating around in your tank that get more concentrated when the tank is closer to empty. Just a thought.

 

[white92talontsi]

I thought the same thing as well. It still does it even with a full tank but it is not as bad. I had the tank out a few months ago and the tank was clean. Gonna snatch the file filter off it tomorrow and replace it.

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[highlandgst]

the locking mine used to do that it would lock after 30 seconds after being unlocked . As far as runing crappy check for boost leak or vac leaks those are the common issues with that . The cutting off could be a mssive boost leak , fuel issue .

 

[williillii]

Sputtering sounds like a bad ignition component maybe...I had a coil that would go in and out while warming up, then it would work fine for a bit, but after alot of driving it would start to cut out...

I would check the main power/ground wires too.

 

[white92talontsi]

the locking mine used to do that it would lock after 30 seconds after being unlocked . As far as runing crappy check for boost leak or vac leaks those are the common issues with that . The cutting off could be a mssive boost leak , fuel issue .

I can hold 20psi from 1st through 5th gear.



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[white92talontsi]

Sputtering sounds like a bad ignition component maybe...I had a coil that would go in and out while warming up, then it would work fine for a bit, but after alot of driving it would start to cut out...

I would check the main power/ground wires too.

I am thinking the same as well. Gonna try a coil on mondays.



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[highlandgst]

well even if you are holding boost doesn't mean you don't have a vaccum leak. I undid a vac line and didnt puti t back on . Car idled up and down and ran crappy and I got compressor surge from it . But I agree with the spark idea also . I jsut redid my spark plugs and my car runs alot better.

 

[white92talontsi]

well even if you are holding boost doesn't mean you don't have a vaccum leak. I undid a vac line and didnt puti t back on . Car idled up and down and ran crappy and I got compressor surge from it . But I agree with the spark idea also . I jsut redid my spark plugs and my car runs alot better.

The nature of the problem pretty much rules out a vacuum leak or a boost leak.

I put a new ignition switch in the car today and im gonna see if that cures the random issue with the car shutting itself off.

I believe it must be something electrical. Im almost leaning towards the ecu now. When it starts spitting and sputtering i can turn the ignition off while still in gear and then turn it back on and the sputtering will clear itself. Almost like shutting the igniton off is clearing the memory of the ecu and the problem clears itself. Sometimes it will come right back and i have to do the key trick some more and sometimes i can do it one time and it will not act up anymore.


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[trevor425]

sounds like a cracked or weak coil to me. pull em and inspect them for cracks or obvious shorts to ground. it will usally leave a chard trace if it they are grounding out.

 

[white92talontsi]

since putting the ignition switch in the car has not shut off anymore but i may leave work today and it may do it who knows.

Have not got around to changing the fuel filter, getting ready to pull the head off this week to change the valve seals. Yea I know it can be done without pulling the head but I need to inspect the cylinder walls and fix a lot of stuff that someone rigged up. So I will put a new fuel filter on it at that time.

 

[white92talontsi]

Found the issue with the car randomly shutting off. The 30 amp fuse for the ignition at the battery was starting too get burned. Probably from the improper wiring someone did when they had the car.

Also about 2 weeks ago when i went to the track i ran 4 gallons of 103 octane. Ran that through for a couple days. The car runs perfect now. No more issues except i cant seem to find this phantom 6th gear. Boy i sure do need it

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