# 2.0 8v (2E) rough idle and slight jerking



## Mr47 (Sep 6, 2007)

*2.0 8v (2E) rough idle and slight jerking & spark plugs are red?*

The car is 1993 Volkswagen Vento(Jetta III), with 2.0 8v (2E) engine.
The problem is, that some time ago, the idle went a bit rough, at first it didn't bother me much, but then it got worse, and now today it started to jerk a bit even when accelerating. 
When idling, occasionally the rpm drops down to like 350 rpm for a sec, and at other times just keeps jumping up and down between like 600-700 rpm really fast. 
The problem occurs both when the engine is cold and when it's warm.
It did appear before, that there was some sort of loss of power, when the engine got to working temperature, but now, it seems kinda "weaker" all the time.
I've replaced the distributor cap, distributor rotor, temperature sensor, air filter, vacum hoses, and spark plugs, but the problem just seems to get worse every day. The old spark plugs seemed to be of very strange color also.
Anyone got any ideas what to do/check?
Picture of old spark plugs:










_Modified by Mr47 at 2:32 AM 6-25-2009_


----------



## mk4slow8v (Sep 21, 2008)

*Re: 2.0 8v (2E) rough idle and slight jerking & spark plugs are red? (Mr47)*

bump i wanna know too


----------



## FL 2.0L (Aug 1, 2002)

Wires and coil. Check 'em out. Look under the hood at night to see if you can see sparks.


----------



## joshsjetta (Feb 3, 2009)

*Re: 2.0 8v (2E) rough idle and slight jerking & spark plugs are red? (Mr47)*

Excerpt from automedia...
"Normal, but with red coating: The red coating is a result of the additives in lower-quality unleaded fuel and will be visible on the plug's ceramic insulation. The red coating is not an indication of any engine problems."


----------



## seanmor (Dec 23, 2004)

*Re: 2.0 8v (2E) rough idle and slight jerking & spark plugs are red? (Mr47)*

Have you checked for vacuum leaks?


----------



## Mr47 (Sep 6, 2007)

*Re: 2.0 8v (2E) rough idle and slight jerking & spark plugs are red? (Mr47)*

Well, i'll check the wires when it gets dark( it's midday here at the moment.
I doupt there's a vacum leak, if i replaced all the vacum hoses?
Also, about fuel, i've only taken fuel from the two major companies around here, and used the "better fuel", here we got 95 and 98, i've been using 98, almost all the time, though, i haven't had the car for all too long, i have no clue whatkinda fuel the previous owner might of used.
I'll check how the new spark plugs look now


----------



## Mr47 (Sep 6, 2007)

So, i checked the new spark plugs... not a sign of anything red on them, but the engine still works same badly. Will update my findings in the evening, about the spark plug wires. *How do i check the ignition coil?*
Also there appears to be strong vibration starting from like 2000 rpm, gets stronger up to 2400 rpm (being the strongest) and then gets weaker again as you rev higher
Picture of the new spark plugs (which have driven like 50 km)










_Modified by Mr47 at 2:46 PM 6-25-2009_


----------



## Mr47 (Sep 6, 2007)

*Re: (Mr47)*

Okay, in the dark, i sprayed some water on/over the spark plug wires... not a single spark or anything whatsoever, no impact on engine work either.
Also, from this schematic, i cleaned #1 (control valve for idling stabilization) with carb cleaner... still no effect







.
I am curious what is #15 on the scheme and what's the thing, that #11 connects to?


----------



## Mr47 (Sep 6, 2007)

I guess it's down to the coil now... or could it maybe be MAF?


----------



## alixjg (May 4, 2008)

*Re: (Mr47)*

Sounds to me like a MAF issue... I would def. try some MAF cleaner. That really helped me out when my engine was chugging and I had a rough idle. Although... it was a few days later... my transmission ate sh*t.


----------



## FL 2.0L (Aug 1, 2002)

Scan it and you won't have to guess or waste more money. Those plugs look like mine did when my coil went.


----------



## Mr47 (Sep 6, 2007)

Well, i was going to buy me the vag-com cable, i do have the software... but it's not so easy to get the cable, as no shops actually sell it, through the local volkswagen club forums some guy was sellin' those, but he has disappeared... so... Going to a diagnostics place costs more than the coil itself








But i'll try cleanin' the MAF. I suppose some carb cleaner would be suitable?


----------



## aa2p (May 25, 2009)

*Re: 2.0 8v (2E) rough idle and slight jerking & spark plugs are red? (Mr47)*

Actually my golf was doing the exact same thing rpms fluctuating like crazy. It's like it had a mind of its own. It threw me a coolant temp sensor code. I replaced it and I have not had a prob yet


----------



## dopeheadonmoped (Jul 3, 2009)

*Re: 2.0 8v (aa2p)*

yeah idk if my plugs are red but my car occasionally wont wanna start and it revs real crazy all by itself....turns out i got 3 CEL codes and one is the Engine Coolant Temperature sensor ...youd never think that a coolant sensor would make your car rev so spazzy but i guess it can really do a number on it...must be thats why these sensors are so cheap...they must go bad quite often..


_Modified by dopeheadonmoped at 4:40 PM 7-5-2009_


----------



## rednecksavage (Mar 11, 2002)

*Re: 2.0 8v (aa2p)*

I am curious about this. My sons car has the same issue. Where is the coolant temp sensor? Is this the blue one with 2 wires coming off of it?








Thanks


----------



## stain_mk2 (Dec 10, 2011)

Ok...i got the same issue right nw. I have a 2E carb. If i tune my timing on th CAM (standard) to 0. It runs okay. But has almost no power or kick in it. If i tune the timing on the CAM to th front 1, its got power, but it has that uneven idle. I tried changing the plug cables, it was fine for a day thn back to it again. Carb cleaner didn help at al. Im stuck man.


----------



## golf mk2 2e carb convers (Oct 18, 2013)

*timing mark problems*

Good morning every one tell me is there anyone with a golf mk2 with 2e engine carb conversion


----------



## B3-Gabby (Dec 2, 2020)

Faulty air flow sensor 👍👍
Unplug your airflow sensor I had the same and since unplugging it's been fine.


----------

