Hello everyone, long time reader, first time poster :) i apologize in advance for the wall of text
I have a weird problem with my car, and was hoping someone might have had a similar issue and can help.
I got the car few months ago.. its done 210.000km.. i moved countries and needed a beater car for long journeys with comfort, until my family and i settle in and get a descent one.
It starts great, runs great, no smoke, etc.. nothing odd for 99.9% of its usage.. BUT .. sometimes, usually on the highway.. it just jolts violently for a second or two.. 2-3 jolts ..and after that keeps going like nothing happened... or does it again in a few km.. or doesnt for a few hundred :(
i cant describe properly how it feels like.. its like its moving a few inches back and forward real fast.. like if you had a manual.. drove at 50/60km/h .. poped the clutch in fifth, revved it silly and dipped it back real fast a couple of times.. or try to shift a diesel into fifth at 40km/h
so as it happens really rarely why am i here? :D
well the local mechanics diagnose it from the door of the shop.. one said engine injectors, one said fuel pump.. one said transmission ecu.. each one had a different guess.. as i plan to sell the car in a year or so i dont wanna "guess" my way out of couple thousand euros :D
i scanned the car with an "audi" diagnostics .. thats what the guy said.. i know he had a handheld bosch diagnostics thingy.. no error codes
then i scanned at a buddy with vagcom .. i got 00550 start of injection regulation / 27-00 implausible signal - interminent .. if someone can shed some light on that, it would be very apresciated as i haven't been able to google that combination of codes anywhere :(
what more info i can give that might help:
-i've read a lot of this forum.. i like to read up on stuff.. fjtwelve's topic kept me awake a few nights xD .. so i know the common issues these cars have
-it starts up great, no smoke.. maybe a puff in the morning, but i think my battery is nearing its lifes end
-no hot start issues..
-the gearbox is running smooth and dandy, no sudden shifts, jolts etc in everyday driving
- i know the guy i bought it from.. the service history seems fine
-it doesnt smoke even under heavy load.. i had a buddy drive behind me and floored it.. nothing out of ordinary
-i cant seem to pin down anything related to why its happening.. i could be going 80, or 200..hot day, cold day, wet, snowy, regular.. can be on acceleration, on decelearation.. just using cruise control
-one or twice i had something similar happen when i was in neutral at a stop light.. i could feel it just shuddered and shut off.. if its related i guess under load it doesnt "drop" enough to shut off
-when it does happen.. the consumption doesnt change.. it doesnt go into limp/safe mode.. i've had a few thousand km done without it happening.. then happen a few times in one trip
-initally i thought it was bad fuel.. felt like that.. but i changed a lot of petrol stations, so i've eliminated that
as i do mostly city and highway driving i'm not too afraid of it as it could be an issue on a B road when overtaking in the oposite lane.. but i'm afraid it could be something silly , causing a bigger problem somehow.
please help, the gremlins are driving me mad.. i love every bit of this car, i dont wanna have to pass it on