95 Golf 2.0 Cold Idle and Hesitation Problems

cgrossl · #1 (**permalink**) 02-02-2009, 10:30 AM

I have a 95 Golf with almost 130K miles on it. The engine is a 2.0 with a manual transmission. I've had the car for about a year, and ever since I have owned it, it has always idled erratically. When sitting at a stop light it would usually idle just fine at 900rpm. But sometimes, it would idle at anywhere between 900 RPM and 2500 RPM, and it would rev up and down randomly. The check engine light would never come on, unless I was driving on the highway for more than 60 miles or so. This was annoying, but it wasn't annoying enough for me to fix the problem so I just let it be.

Now, I have a more annoying problem, that may or may not be related to the aformentioned idleing problem. Anyway, when I start the car when it is dead cold, it will not idle. It starts right up, but in order to keep it running, I have to hold it at 1500-2000 RPM for a few minutes, or just start driving it. After it warms up, it idles fine. After it warms up, if I let it idle for more than a minute or two, it will jump and hesitate if I am accelerating normally, and during cruise. If I accelerate rapidly, it does fine. If I shut the car off momentarily, and start it back, it will run and accelerate just fine until I am in a situation where it has to idle for a few minute again. Fuel consumption has decreased during all of this by about 10%. The car did briefly go back to running like it did when I bought it for a few days, but it has since returned to the no cold idle/hesitation mode, previously described.

The check engine light did come on for a few days, but I was unable to get any trouble codes out it. I was using the jumper wire on pins #4 and #15, while the key was on. I held the jumper in place for 3-5 seconds, then released, but the check engine light never flashed. Maybe I'm doing something wrong?

I am planning on doing a full tune up, including a new oxygen sensor, which I am sure that the car needs. But I don't think that it will take care of the problem. I did so a search through these forums, but I never found anything that directly related to my problem. Anybody got any ideas on where I should start?

Thanks,
Cameron

natsirt · #2 (**permalink**) 02-02-2009, 05:39 PM

I'm thinking your wires and spark plugs may have gone to s***. Have you replaced them or even checked them? Remember, even though you haven't seen the CEL come on, it doesn't mean it isn't there. The previous owner could have simply removed the bulb for it from behind the instrument planel.

Check this out:

VWvortex Forums: mk3 golf bad obd reader

This is a discussion from a different VW Forum that explains exactly how to display the DTC with CEL on the dash. Read it.

I used it to figure out any faults on my Golf.

**THIS ONLY APPLIES TO OBD-I VWs**

Good luck.

keehn · #3 (**permalink**) 02-03-2009, 05:30 PM

I'd suspect the idle air control valve. Try cleaning it or replacing and see what happens.

Mike (MKIII Emeritus)

cgrossl · #4 (**permalink**) 02-06-2009, 08:41 AM

I've tried that method that natsirt posted a link to, for getting the check engine light to flash trouble codes, but I could never get it to work. I'll give it another try over the weekend.

I''ve also noticed that if I don't let the car idle, it will continue to run fine. If I let it idle at a stop light or something, for 30 seconds or so, it will start hesitating and jumping during normal acceleration, and during cruise. If I shut the car off for a second, and restart it, the problem goes away until I let it idle for too long again......weird.

Anyway, I am going to try a complete tune up first. I know that it needs it. I'll give the IAC valve a good cleaning while I am at it.

Thanks,
Cameron

abetterreason · #5 (**permalink**) 02-06-2009, 04:36 PM

i agree, mine does the same and it was the iac valve. could be plugs, wires or o1 sensor though

keehn · #6 (**permalink**) 02-06-2009, 06:52 PM

Quote:

Originally Posted by abetterreason

i agree, mine does the same and it was the iac valve. could be plugs, wires or o1 sensor though

No such thing as an O1 sensor... It's called an O2 sensor for a reason...

Technically, O2 is known as "dioxygen", but to us laypeople, it's just the air we breathe. In chemistry, there would not be any such written element as O1...it would be simplified to merely "O", since there is just one molecule present. I would hate to read the chemical formula that had "1" after every mono-atomic molecule...(N1a1C1l1 anyone?)

Kiddie chemistry lesson is over...

Mike (MKIII Emeritus)