ok so just replaced my headlight/combo switch and everything went super smooth, reconected the battery and everything works good. i go to start the car and it barely runs. it idles at like 300 rpm and wont go past 1200rpm, it just cuts off. with a little foot pumping i can get the revs up but they wont stay. what the hell happened? i dont have a vag com yet so i cant read any codes. please help me out.

 

Year? Engine? Since the battery was disconnected you should start with a throtle body alignment. If you know someone with vag com do it that way, if not, turn the key to on without starting and do not press gas pedal and wait 5 mins or so and then see what happens. If that fails get a ride to autozone, some locations will let you borrow (with a deposit) their OBD scanner.

 

'98 1.8tq. i tried turning the key on and letting it sit, still nothing, runs like crap. so you think it is a throttle body alignment? will the basic scanner do that?

 

Are you sure you didn't accidentally disconnect a ground or accidentally short something out that could send it in to some kind of limp mode?

 

nah thats not limp mode. its most likely the adaptation didnt work, or possibly you have a leak somewhere or bad maf for some reason. or else while you were in the steering column replacing the switch you did something to make the immobilizer not like you. although that usualy just shuts the car off after 2 seconds, it wouldnt make it idle like that. my money is on the TB adaptation didnt work for some reason. a basic scanner wont re-align it, you need vag-com or to bring it to a dealer to do that if the 'turn key to on for 5 minuit' method doesnt work. the basic code scanner will however tell you why its running like this.

 

so, i just rented a scan tool from the parts store and it was the throttle body alignment. cleared the code... tried the key on for 5 min. thing again... nothin. im going to have to get my car towed to the stealership... damn, this sucks. seems like nothing can ever be easy with these cars!

 

with the money you spend on a tow plus what the dealer is going to pork you for the 30 second TBA you could buy a copy of vag-com and do it yourself, and have the ability to fix future problems yourself.

 

Sounds like a simple vacuum leak. Double check your intake hoses, and also there's a hose right behind the brake booster, make sure that's on there tight too. I've had both hoses come off on separate occasions and it ran like crap and wouldn't stay on idle until I plugged the hose back in.

 

did you ever figure this out?.... my car just started this $#!^ after I seafoamed it.

 

I would check your spark plugs I know sea foaming is to help get rid of carbon but it seems to me it could build up something on the plugs. That's just a shot in the dark though you didn't provide any info on how YOUR car is running. Symptoms? Codes? How did you do the Seafoam treatment? Does the CEL flash? 1.8t or 2.8? Give us some info.