My 2002 Jetta sometimes seems to skip or catch while the car is running. Sometimes the car has trouble starting if it is too humid. Thought it was spark plugs and wires, so had them replaced. But, car is still running oddly. Any ideas why?
I would suggest getting the codes read as a first step. AutoZone, Advance, or (horror of horrors according to some), even Checker/Schucks/Kragen will do this for you free.
Post any results back here for further discussion.
You might also consider spraying the coils down with WD-40 and see if the problem goes away. Engine not running of course since WD is flammable.
Thanks for your reply. About 6 weeks ago, I took the car to Midas and they ran all sorts of tests and said everything came back ok, but it was showing I needed new plugs and the wiring was bad. So, these were all replaced (or so I was told). Additionally, back in May I had to have a new water pump put in. When the car was acting funny in August, I had Midas check the timing belt when they ran the other tests to see if it might be the problem, but they said it was ok. Should I take it somehwere else to have a second opinion on the belt? Maybe they used the old wiring when they put in new plugs? The engine light flashes when I drive. Sometimes it then goes off, sometimes it stays on. The car is still running, but on wet or humid days it will have trouble starting, or stall within the first few minutes of being used… Any ideas? I don’t want to damage the car by continuing to drive it, but I’m also afraid of how expensive the problem might be…
It’s not likely at all that the timing belt has anything to do with this, although it is a good idea to keep track of the recommended replacement interval.
I would think that if they replaced the plug wires it should have been spelled out on the copy of the repair order you received; unless they gave you a generic receipt of some sort showing only a total. (I hate those. Informationless copies of anything is not much of a reference later.)
There’s not much I could offer here except to reiterate that you take the vehicle to one of those parts houses I mentioned and have them pull the codes. As I mentioned, they will do this for you free. Post any results back here for further discussion. Do not ask the parts house employees to diagnose or interpret anything for you. That is not their job. They only pull the codes to aid you in hopefully going the right direction.
Offhand, it does sound like a plug wire or coil problem and this really should be rememdied rather than be allowed to continue.
Years ago I had a car that wouldn’t start if there was a cloud in the sky. After several mechanics failed to solve problem, including plugs & wires, one guy took the computer, which was inside car on the side, and wrapped it tightly in a plastic bag. Voila! The car was what we called a ‘squareback’. Not sure anymore, but wasn’t that a VW?
Yes, that was the VW air-cooled. It used AFC fuel injection back before injection was cool.
It worked pretty well with the main problems usually being related to the temperature sensor, dual relay, or the extra contact points inside the distributor that operated the injectors. In some worst cases, a backfire would blow the flap out of the airmeter.
My guess is that moisture was affecting the computer circuitry or the multi-pin connnector. The computer was located inside the right rear fender.
A good friend who used to live in another state many years ago told me about a VW squareback that was quitting at odd times. It was towed in repeatedly but at the dealership it would always start and run fine. They could not make it screw up.
Of course there were no codes to pull on this system.
The owner happened to mention that it quit at the same time in the same spot when it did this.
A bit of investigative work turned up the fact a new radio station had a tower beside the expressway. They were off the air from midnight to 6 A.M.
It was discovered that if he happened to be going by that tower on the way to his new job at 6 in the morning the momentary surge from the tower when it came on would screw the computer in the car up.
Found a new way to work and no more problems. Just when you think you’ve seen it all… 
When I originally had the problem diagnosed by Midas, it said “code found was PO302 and cleared”. “misfire ck #2, plug, wire.” I had the neighborhood garage replace the plugs and ignition wires (they list both on receipt). I’m going to AutoZone today for the free code reading and will post results. Thank you! We’re hopefully getting closer to solving the mystery…
I had the codes read - 3 came up. They were 0300 Misfire, 0302 cylinder #2, and 0304, cylinder #4. Any advice based on these readings?
ps. My car barely made it to the shop to have these read. The mechanic checked the wires, jiggling them to make sure they were attached, and then reset my car’s computer so the engine light - which had been flashing - would go off. The car ran ok after that, not threatening to stall, but still skipping every now and then…
Since the plugs and wires have been changed my feeling is that since you have a multiple misfire (more than one cylinder basically) the problem is going to be related to the coils or possibly the Crank Position Sensor.
You might call a nearby VW dealer and ask about an ignition coil recall or campaign. The '01 and '02 VWs had some ignition coil problems and if your vehicle’s VIN in included then VW should repair this for you free.
I do not remember if this was a recall (meaning VW WILL cover it no matter the mileage or number of owners) or a campaign (which means a non-mandatory PR effort to fix the problem).
My memory is pretty hazy on this but it may not have applied to the 12V V-6 engines and I’m unsure as to which engine you have.
The dealer should clarify all of this for you.
Hope some of that helps and keep us informed.
(I would also do as little driving as possible until this problem is solved. It just exacerbates the problem even more.)
Thank you! Will call VW in the AM to see if there has been a recall or campaign. Will keep you posted…
You were right on it being the ignition coil! I took the car into the shop and said it would be that or the crank position sensor. The garage called back and said all checked out ok, the car was fine. I said, look harder and did you check the coil - they said they read the codes only. I explained the car wasn’t running well and to go back and check the coil like I requested. And, yep, the coil was bad. You hit the nail on the head. Thank you! My local dealership and VW services said there hasn’t been a recall or campaign to address the 2002 VW Jetta V-4 ignition coils. So, sadly, I’m paying. This car is becoming very expensive and it’s not that old yet! Thanks again!
For future reference:
VW’s have an advanced computer that stores more codes than most readers can read. Only a VAGCOM can read all the codes and they can make additional adjustments as well. Anytime you don’t get a good answer from the ggeneric readings find someone with a VAGCOM and try that.
Also there is no way to look at or test a timing belt. They have an expected life (different for different engines and years). You will find the recommended change interval in your Owner’s manual. Make 100% sure you change it on schedule. Failure to do that can cost you an engine.
Glad to hear you find the problem.
Volkswagen timing belts have been known to fail BEFORE the mileage specified in the manual. If the car still has the original belt, and the car is over 50,000 miles, change it pro-actively! I believe the normal interval is 60,000. My neighbour’s wife had hers go before 60,000 miles with the car still under warranty. It caused nearly $3000 damage to the engine. The dealer gave her a hard time, but she won and got all her repairs paid for, including a new belt.
Well, after a week or driving, it’s still not running right. My guess is it is the timing belt (could I have also needed the ignition coil, new wires and all new plugs at the same time?). I don’t think I’ve had a new timing belt put on since I bought it. This car is costing me a fortune!