Rough idle on cold start up
 

Hi all:

VW New Beetle, 2001 1.8T, manual.

I have a rough idle for about 20-30 seconds cold. It often sounds like a consistent one cylinder miss with an intermittent rolling miss. I have the Ross Tech VAG 1551/1552 and pull the random misfire code (16684) and 16687, 16685 & 16686 individualcyl misfire codes.Although I have ocassionally seen these codes before, there were no drivability problems. This current situation started the other day with abad #3 coil over pack that failed creating real drivability problems; I traced back all wiring into the harness repairing any broken insulation (numerous), confirmed voltages on all coilover pack connectors and pulse from the ECU, replaced plugs and the #3 coil (confirmed bad). All of the problem was resolved except a cold start miss (never happened before). After the initial warm up period, 20-30 seconds, the car runs perfectly in all driving conditions and throws no codes. My O2 sensors are reading fine but I'm always suspicious of sensors over 80K mi (car has 98K). I hear no vacuum leaks and all hoses seem fine. Any ideas anyone?

Thanks in advance for your help!

Uppi

RE: Rough idle on cold start up
 

Hey, I have the exact same car, and same year, but I have 60K miles.... I have never had that prob. but I can tell you that it might have something to do with the MAP and MAS sensor,..... I have had a my bug for 3 months now, and the only prob. I have had was that just on the thanksgiving, my turbo blew up.... but with the rough idle,.... you crank sensor, could be a lil off, and your MAS sensor could see that its colder than it really is, and telling the computer to give it more fuil. I have a stage 1 MAS, and a Stage 1 Turbo going in it today, and a new After market Exhaust system, and when I put the stage 1 MAS in, at first it had a rough idle, but that was because the computer was not used to seing such new numbers..... but look at the MAS, and MAP, ( Map is located on intercooler, just behind the right turn signal on the bumper, just incase you weren't sure). so just look at those two, and I hope that I have given you so idea of what to look for. good luck, and I hope you can fix the problem...

whats up guys...i also just developed a rough idle but it seems to be more of a "miss" that continues up untill about 3,000-4,000 rpm..ive checked for vacuum leaks..etc...MAF sensor possibly? my car is a 2003 new beetle turbo "s"

i would also like to add...that this problem started after a really long idle ( about 15 minutes)

Hello Erica. I like a girl that can work on her car. Well, it could be a lot of things. If you want to clean out the MAF make sure you only use electronic cleaner or they make MAF cleaner. If you could explain the problem with a little more detail, maybe we can get it narrowed down.

ideling problem
 

i have a 2000 Beetle 2.0 when i start the car it idles fine but when i give it gas it doesn't take the gas and rpm does not go up untile it warms up then i have no problem any help there?
thank you

actualy not ideling problem
 

my beetle ideals fine but when i give it gas it won't take it. aftewr i posted the first thread my car started to work fine with no problem for couple of days and after driving for 30 min. i stopped and when i started it it acted up again for 30 sec. where it wouldn't take the gas then it was alright

Don't forget the possibility of a bad o2 sensor..ive read it in hypertech.com that bad o2 sensors can cause idling problems..

got mine fixed....it was a bad coil pack so i just bought a new set of the audi e type coil packs...runs like new!

Rough idle on cold start up
 

Its sliiiggghhhtly ruff maark lol btu i would lose the lettering and just have the axe and spear isih lol and sheild but im sure a decent artist could do wonders with it