Volkswagen Mark IV Forum banner

1 - 20 of 34 Posts

·
Premium Member
Joined
·
6,442 Posts
Discussion Starter · #1 ·
Sat still in traffic last night and the engine started idling erratically and shaking badly, moving off there was little power and engine felt lumpy, and sounded like a tractor, any ideas what could be the fault? Felt like an engine mount with the way the car shook but that wouldn't cause any power loss, MAF was replaced last month.
 

·
Registered
Joined
·
1,964 Posts
David,

I see you have an AGU like mine [:D].

Did it feel like a miss-fire ? Could be your intermediate stage on the back of the airbox, take the connectors off and clean up the contacts. Scrape them with a blade or use some emery cloth. I use spray contact cleaner on the loom side.

Give that a go.

Paul
 

·
Premium Member
Joined
·
6,442 Posts
Discussion Starter · #4 ·
Did it feel like a miss-fire ? Could be your intermediate stage on the back of the airbox, take the connectors off and clean up the contacts. Scrape them with a blade or use some emery cloth. I use spray contact cleaner on the loom side.
Yeah, does sound like a miss-fire.

There's 2 connectors on the airbox isn't there, is it one of those two?
 

·
Registered
Joined
·
3,756 Posts
I had this last year....exactly like you stated above. Very little power, engine idle all over the shop.

Just cured itself.

Never found out what was wrong.
 

·
Registered
Joined
·
1,964 Posts
Did it feel like a miss-fire ? Could be your intermediate stage on the back of the airbox, take the connectors off and clean up the contacts. Scrape them with a blade or use some emery cloth. I use spray contact cleaner on the loom side.
Yeah, does sound like a miss-fire.

There's 2 connectors on the airbox isn't there, is it one of those two?
Yes there is a module bolted to the back of the airbox with two connectors, you need to clean them both up, to release them you push the small metal bar in and the pull the connector off.

Paul
 

·
Premium Member
Joined
·
6,442 Posts
Discussion Starter · #7 ·
I had this last year....exactly like you stated above. Very little power, engine idle all over the shop.
Might be, happened last night in that big downpour so something could have got damp.

Cheers Paul, i'll try cleaning those connectors tonight
 

·
Registered
Joined
·
558 Posts
the engine started idling erratically and shaking badly, moving off there was little power and engine felt lumpy, and sounded like a tractor,
Sure somebody didn't nick your engine and put a diesel lump in there?
 

·
Premium Member
Joined
·
6,442 Posts
Discussion Starter · #9 ·
I had this last year....exactly like you stated above. Very little power, engine idle all over the shop.
Might be, happened last night in that big downpour so something could have got damp.

Cheers Paul, i'll try cleaning those connectors tonight
No luck. The car feels exactly the same with the MAF dis-connected too.
 

·
Registered
Joined
·
445 Posts
Could it be a dodgy maf again, but maybe caused by crap air filter or poor seal allowing stuff to get through/around it?
 

·
Registered
Joined
·
2,164 Posts
I had a similar problem on my car a few weeks ago.The AA Checked the
coil packs, plugs, compression, ignition amp module thingy, injectors,
all were ok and i had no CEL on the dash.I also tried disconnecting the
Maf and swapping out the temp sender and still no change.

When i let the car cool down it would start fine with no misfire.A few minutes down the road the misfire would return.

Took it to a bosch injection
specialist and turned out to be a faulty ecu.Had to send it off to repaired.
 

·
Registered
Joined
·
2,164 Posts
how did the car behave when you disconnected the maf?

If it was the maf it should drive better unplugged. You will boost less tho.

Worth a try if you have not tried already.Do you have AA or equivelent membership ?
 

·
Registered
Joined
·
2,164 Posts
Same as mine was.Does it still misfire when starting from cold ?

Id call the aa out and get them to give the car a look over.They will
be able to hook it up to their diagnostics laptop and check for faults
too. I was reluctant to call them out for my car a few weeks back
but was glad i did.Really impressed with the service i got from the guy
that came out to my car.He really gave the car a proper check over and
although he was unable to find the problem he was pretty sure that it
was an ECU fault and he turned out to be right.

Worth a stab before you fork out any money changing parts.
 

·
Premium Member
Joined
·
6,442 Posts
Discussion Starter · #17 ·
Yeah, it mis-fires from cold.

I'm drop it off at a local VW specialist in the morn and see what they say, they supplied the MAF
 

·
Registered
Joined
·
2,164 Posts
Hope its something simple like that.

Coilpacks on the older engines like ours usually dont fail. Its the
newer ones with the integrated ignition amp in each coil that goes
afaik.
 
1 - 20 of 34 Posts
Top