my car's runnin really rough

[stinkysGTI]

Hey guys, I've been away for about a month, but now I'm back.... with a problem :(

when I was parking last night, I had a slight roughness in the engine; barely noticeable. Then this morning on my way to an interview, it ran just fine. Then after the interview I got in my car to leave and noticed right away somethin was wrong.

The RPMs were wobbling between 600 and 800 and I could hear the engine missing. When I put a load on the engine, it runs really choppy and sputtery and will randomly backfire. I can accelerate smoothly, but only when I barely apply any pressure to the accelerator. Anything more and it runs like crap.
Also, my auto windows arent working and the outside temperature display was stuck at the temp it was when I had arrived at the interview. I reset the computer and the temp was working properly again, but nothing else.

When I got on it for a bit, the check engine light started flashing and would stop [light off completely] if I let up on the accelerator a little. I looked it up in the manual and it said if the light's flashing, my cat could be messed up.

That doesnt explain why its running rough though. From my past experiences, this kind of roughness is usually caused by the ignition coil, plugs, wires, or distributor.

I checked all of the plug wires on the dist side and I just installed new plugs [iridium] about 4 months ago.

I'm rather new to having an ass load of wires and sensors and the engine bay [all previous cars have been old] so I was hoping someone here might be able to help before I go and spend money.

Any help would be much appreciated and if you need any more info, I'm more than happy to give it.

Could the wires be bad even though they appear to be ok?

thanks guys

[MrBurritoMan]

its not that a wire might have gone bad (however that might be a possibility) its more or less that the connections have gotten dirty or fowled. i would check all of your grounding straps and connections to the coil. it sounds like this is a bad connection because it was sudden and rather sporadic. i know that for some reason the Germans loved to cover the grounding straps and such in wax for some reason in the Mk3. it might still be true in the later models however im not sure. i would make sure that everything is solid and if you have a multimeter whip that out and check a few things. with it i would connect one end to the block and the other to the negative pole on the battery. measure the voltage with which you should get 0.00v, then click it over to resistance (ohms) it shouldn't read anything more than 1-2ohms. anything more and there is a dirty/loose connection somewhere.

[stinkysGTI]

i fixed it and came across a useful tip
i tried cleaning all related electrical connections and it didnt do anything the problem was the #3 and #6 wires were bad so it was misfiring.

i got a tech at a VW dealership to run the computer for free :D AND he showed me how to bypass the double grounding issue that vdubs have where the stereo wiring harness is.

I had problems with running a diagnostic computer on my car for a while. I tried 3 different computers and all failed. It was because I have an aftermarket stereo and here's how to bypass it...

1. Pull your stereo out completely [no connecting wires] and set it on the floor or somethin.
2. Pull the wiring harness that was connected to your stereo out as far as possible.
3. You'll see a small black box that the wires feed into; and on the other side should be 2 small harnesses that connect into that single harness.
4. [for my car - 01 gti vr6, one was black, and the other was brown] Remove the black one, ONLY
5. Now, run the OBD2 computer like normal

After you remove that small harness, it should read and erase just fine.

If your harnesses are different colors than mine, just try one, then the other.


I thought I'd post this just in case cause I've heard a lot of people having this problem of failed readings.

hope this was helpful....