Volkswagen Passat (1988 - 1997) - 96 2.0 Poor running, hesitation.

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Sat 4 Jul 2009 02:03
96 2.0 Poor running, hesitation. - cphardcastle
My Passat developed an intermittent hesitation a few months ago which has progressively become worse. At first it would only happen once in a blue moon but now it's getting to the point where I'm not sure I want to drive it for more than a few miles.

It normally happens when trying to maintain a speed on an incline. The car then feels hesitant and you can feel that it isn't happy - at one point this afternoon it was so bad I almost thought I was running out of fuel. If you accelerate sharply for a brief second or two it clears but soon comes back within another few seconds.

I had a routine service by Tune Up about a month ago and when I advised of the symptoms (although they weren't so severe or common then) a fault code was found in the system - lambda lower limit error indicating that it was running rich, I hope I've got that right, I know nothing about such things?

Unfortunately Tune Up didn't have the time to investigate the problem fully (and in fairness I didn't tell them of the fault until they'd almost finished the service as it wasn't so much of a problem then) but they did disconnect the fuel tank vapour condensor which feeds into the inlet manifold to see if this might be causing the rich running. Unfortunately this had no effect on the problem and I'm in the dark as to what else it might be and I don't want to start replacing expensive parts that don't need replacing and won't solve the problem.

I've checked all the vacuum hoses and crank case breathers for leaks but they all look ok to me. I've also removed and cleaned the throttle body as somebody suggested that this might be to blame, but to no avail. Somebody also suggested that the coil and ECU relay can cause similar symptoms when they go bad but I doubt either of those parts failing would prompt an O2 sensor error?

Just to throw this in I also have an annoying resonance coming from what sounds like the exhaust midsection at about 2500 revs. Could my catalytic convertor have packed up causing the O2 sensor to fail or 'see' the wrong thing?

Along with the problem I've also noticed a drop off in performance and throttle response but interestingly fuel consumption doesn't seem to have been adversely affected.

Any help/suggestions gratefully received.

Thanks in advance,

Chris
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Sat 4 Jul 2009 08:54
96 2.0 Poor running, hesitation. - Vinnychoff
Chris ideally you need access to a meter that will pick up the error codes and then test the parts that are mentioned. i bought a cheap tester from ebay, hong kong for mine. not sure which tester fits on yours. if you have a search on the net you should find out how to test the lambda sensor.
hard to guess which part is faulty
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Sun 5 Jul 2009 20:39
96 2.0 Poor running, hesitation. - cphardcastle
Thanks for your reply.

I thought that might be the case, I guess it's one of those problems that's not as cut and dry as I'd hoped it might be.

I'll invest in a fault code reader and see where that takes me.

Thanks again,

Chris
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