HELP with misfire ABF 16v 2.0

[ratcatcher]

I have a GTI mk3 2.0 16v 1997 engine ABF with 186,000 miles—original clutch and exhaust and it does not burn any oil..!!!!!!

I need help with the following problemÂ…Â…..

When cold its very difficult to start.

When hot tick over is lumpy with the odd misfire. When I try to accelerate below 2500rpm I get massive misfire, seem like only firing 2, if I drop a gear and get rpm above 2500 all is fine. I can go all day at 70 and all is ok but come to a junction and it misfires below 2500.

When I had this problem 3 months ago I changedÂ…Cap,leads,rotor arm,coil,plugs and main Relay that was suggestedÂ…. then I found it was the vacuum pipe between manifold and ECU, once replaced all was okÂ…. I have checked all pipes as best I can this time.

I wonder if it could be a sensor somewhereÂ…Â…HELP

[rubjonny]

I'd start with the ECU temp sensor, its on the side of the head I think?  Also check all your inlet boots and vac hoses.

[Len]

When you said you changed the main relay which one?
Common fault on Mk 3's is either the ECU relay or the Fuel Injection relay.

[ratcatcher]

Hi

I changed the ECU relay...... engine runs fine above 2500 so i assuned injection relay ok or was that wrong??

[mattosmoknd]

has the throttle body been cleaned out?

[ratcatcher]

Not touched Throttle body...that was suggested last time before i found the vaccum pipe gone.

How would Throttle body affect the cold starting??

[Len]

Well relays are easy to check!
Take car for a run to warm up. Then stop!
take out the offending relay and if warm to touch then its fine, if cold replace it!

[mattosmoknd]

from what i understand the throttle body opens and closes to allow different amounts of air in when the throttle is applied.... when it's clogged up the disc that rotates open and closed can get jammed..... so if it's open it will always flood the engine with air and generally feck it up... But it is very easy to do yourself or about £20 for a garage to do.... even if this doesn't end up being the solution to this specific problem it will make your car much nicer to drive.. my gti has done just over 100k and it needed cleaning so if yours has done all thos mile then it'll probably need doing!

[ratcatcher]

Finally found the problem....................

Despite having a new coil 6 months ago and it showing a spark at the plugs the fault was the coil pack and another new one fixed the problem....