Mis-fire problem

[wibble111]

Hi all, i have a problem with my 1.8t, basically i went to work this morning the car was sound, when i left it was only firing on 3, so i bought a new set of plugs (the old ones were ready anyway) fitted them and it ran sweet as a nut.
just been out in it again and now the misfire is back again...anyone have any reccomendations as the next step, ive checked the header tank and it seems ok (no oil present)

could it be the coil packs? (i think this is what theyre called)

any help greatly appreciated

 

[Dave_Bayern]

What year? Could be the igniition control module...

 

[madvw]

cheapest and most likely next is coilpacks.

 

[Dave_Bayern]

If its a pre -99 car, then the coilpacks work in a completely different way, and the bit that goes faulty with coilpacks in the facelift models is directly relational to the ignition control model in the older cars.

Hence its important to know what year car.

 

[Jampublic]

When my MAF failed I was getting miss fires on all 4 cyclinders, so I ran it unplugged and all was fine! So replaced the MAF!

Just my 2 pence worth, if you do unplug the MAF & try running it, it will throw up some fault lights EM & ABS!

 

[wibble111]

thanks for the response, its a 98 s reg. bit of an update, ive had each coil pack unplugged in turn & narrowed it down to one (far left when in front of car) so i took the coil pack off sprayed with duck oil and its worked a treat so i think i need a new one.

am i better off with standard or can you get uprated ones maybe??

 

[madvw]

standard only, just replace the lot, and keep the rest as emergency spares.

 

[wibble111]

more of an update and request for help really, the misfire is still there, ive ruled out the coil packs now due to some swapping and changing, but i dont know what to do next before its stealer time.

any suggestions greatly appreciated, cheers.

 

[Jampublic]

Have you VAG.com? Have you tried unplugging the MAF??

 

[walder]

hmm....i had problem when i ran the petrol low , felt like it was running dirty ie fuel pump or filter , well got that replaced with its service but still seemed to drive on only 3 cyclinders

took it to a spark as the mechanic felt it was a electrical fault no signal being sent from the brain to the cyclinder to fire ( this after checking all coil packs etc)

well then the spark found out that it wasnt cyclinder 3 buy 4 and it there was no compression in the cyclinder , it was running at 210 or something compare to 900 or a 1000 to the rest cant even rememebr the unit of cal.

FINALLY bet ur glad to hear , took it to a specialist to run a decompression test well they discovered it was a nat / not sensor????

basically it amplified the signal to the cyclinder and it was ******** hence the lack of compression was 140 pound replaced and fitted hope it helps

but then again he said mines was a special case as with most problems with my cars never a flat tyre or blown fuse lol!!!