Author Topic: My Jetta 1.8T throwing CEL occasionally..... (Read 882 times)

aquadorhj · « **on:** March 13, 2011, 11:42:10 pm »

it still runs great, by the way.

BUT. when i'm at a stop light and idling, engine fully warmed, it will occasionally drop the rpm to 5-600 then catch itself. CEL is thrown.

happened twice in about 2 month. first time, it(CEL) went away in couple of days.
today it happened again.
I do have premium mixed with 89 octane in the tank right now. i'll fill up with premium again. i would say that i only mix 89 very seldomly. otherwise, it's always petro can 91 or esso 91.

i should take it in to mechanic for oil change soon anyway, but thought you guys might have some ideas.

I browsed some vw forums. some similar issues are reported, but clear solution doesn't emerge. they talk about MAF, O2 censor, throttle body, fuel filter, fuel pump, injector, ignition coils etc. etc.

that's pretty much everything attached to the engine.

my engine still runs strong, no loss of power, no loss of engine oil, or excessive temperature or anything. turbo comes on normally. power stumbles a bit right at about 2800-3000 rpm, but it's been doing that since i bought it.

any ideas?

thanks, gents.

Turbo Bob · « **Reply #1 on:** March 13, 2011, 11:45:25 pm »

Seems to be a lot of VAG issues out there right now.

PJungnitsch · « **Reply #2 on:** March 13, 2011, 11:46:01 pm »

Did you get a code off it?

aquadorhj · « **Reply #3 on:** March 13, 2011, 11:50:53 pm »

no sir, i do not have a code yet.

mmret · « **Reply #4 on:** March 13, 2011, 11:55:28 pm »

Misfiring cylinder. New plug / wire or something needed. That is all I have to offer

This likely doesn't help you but I had the same thing in my old Grand Am (what a terrible car). Basically with 3 people and up a slight incline it topped out at about 90km/h.

aquadorhj · « **Reply #5 on:** March 14, 2011, 12:00:55 am »

Quote from: mmret on March 13, 2011, 11:55:28 pm

Misfiring cylinder. New plug / wire or something needed. That is all I have to offer

This likely doesn't help you but I had the same thing in my old Grand Am (what a terrible car). Basically with 3 people and up a slight incline it topped out at about 90km/h.

it definitely feels like misfiring cylinder.. but only happens when the idle rpm drops at a light. my car's power is fine. above mentioned power stumble only happens when i'm near WOT(or 50% or more, i should say). when i'm gently cruising past that rpm, it is perfectly normal.

mmret · « **Reply #6 on:** March 14, 2011, 12:10:51 am »

Quote from: aquadorhj on March 14, 2011, 12:00:55 am

Quote from: mmret on March 13, 2011, 11:55:28 pm
Misfiring cylinder. New plug / wire or something needed. That is all I have to offer

This likely doesn't help you but I had the same thing in my old Grand Am (what a terrible car). Basically with 3 people and up a slight incline it topped out at about 90km/h.

it definitely feels like misfiring cylinder.. but only happens when the idle rpm drops at a light. my car's power is fine. above mentioned power stumble only happens when i'm near WOT(or 50% or more, i should say). when i'm gently cruising past that rpm, it is perfectly normal.

I wonder if its unrelated problems. When you're moving more quickly, its possible that the energy in the car's motion (and pistons etc.) is so high that one cylinder misfiring isn't noticeable. At least this was the case with the Grandma.

Are you noticing abnormally high fuel consumption?

aquadorhj · « **Reply #7 on:** March 14, 2011, 12:19:06 am »

fuel consumption is perfectly normal for winter gas. last fill up was about 10L/100km. i usually get about 10L to 11L per 100km during moderate winter.

vdk · « **Reply #8 on:** March 14, 2011, 03:20:03 am »

I'm thinking MAF sensor. These usually go.

onearmed · « **Reply #9 on:** March 16, 2011, 05:49:34 pm »

Just scan it and that should give you the answer. My most recent problem (no CEL) was the crank position sensor. Car had some fluctuating RPMS then the engine would cut out completely when driving after 20 mins. 1.8T around 180000km.

My ratio of 1 repair per year is still going strong with this VW. Our civic has had 0 repairs in 8 years, I've had 2 repairs in the past two years alone.

tortoise · « **Reply #10 on:** March 16, 2011, 07:42:27 pm »

Protege's commonly have this symptom and it's usually a clogged EGR Valve. But yeah, it could be one of a lot of things.

rrocket · « **Reply #11 on:** March 16, 2011, 07:45:11 pm »

Quote from: tortoise on March 16, 2011, 07:42:27 pm

Protege's commonly have this symptom and it's usually a clogged EGR Valve. But yeah, it could be one of a lot of things.

+1. I was going to say EGR too. You usually notice a faulty EGR when slowing down for a light or something...

articsteve · « **Reply #12 on:** March 16, 2011, 08:14:10 pm »

What year, what mileage?

aquadorhj · « **Reply #13 on:** March 16, 2011, 10:59:30 pm »

03, 110,000 km on odo.

hmm. egr. once i had cleaned one out of my old saturn. didn't do anything.

I haven't made an appointment yet, but i'm not worried yet.

might be good idea for me to get AMA membership, i suppose.

rrocket · « **Reply #14 on:** March 16, 2011, 11:02:50 pm »

Quote from: aquadorhj on March 16, 2011, 10:59:30 pm

03, 110,000 km on odo.

hmm. egr. once i had cleaned one out of my old saturn. didn't do anything.

Cleaning isn't enough. LOL They are controlled electronically....and it's usually a problem in that regard

dr_spock · « **Reply #15 on:** March 17, 2011, 12:52:01 pm »

Coil packs? Wires to spark plugs?

As others have said, scan it. Dealer or someone in your area with a VAG scan tool.

aquadorhj · « **Reply #16 on:** May 04, 2011, 10:41:29 am »

so i had a local shop look at the car while having oil changed for the spring.

turns out it's thermostat. so i had them change the thermostat and coolant temp sensor.

runs alright. still some stumbles while idling.

so, i went out and picked up some air filters, and fuel filter last sunday.

switched them out with new ones.

air filters were filthy, couldn't even see any light thru.

fuel filter, i had to jack my car up for that. took me about 45 minutes, because i couldn't find the release tab. messed up the tab a tiny bit, but managed in the end.

old filter didn't seem that dirty by looks of things, but my car idles a whole lot smoother now.

air filter, $20
cabin air filter, $20
fuel filter, $25
satisfaction for working on my own car, priceless.

mrthompson · « **Reply #17 on:** May 04, 2011, 10:51:10 am »

dr_spock · « **Reply #18 on:** May 04, 2011, 11:30:52 pm »

Good work.

Wanna do our cars next?

aquadorhj · « **Reply #19 on:** May 05, 2011, 10:33:28 pm »

haha, i don't mind getting down and dirty to help a fellow car guy.

i may need to do some more maintenance items this summer, maybe spark plugs? i know that front antiroll bar bushings are squeaky when hot, but don't want to replace them yet..

man... cars are a money pit.