miss fire untill coolant temp reaches 90c..

[vr6goose 0]

hi everyone having a weird problem that started randomly friday before last my VR (obd2,96) miss fires on 2 or more cylinders for 5 secs @ a time untill the coolant temp reaches 90c..

that led me to believe temp sensor was dead but I hooked it up to vagcom today & had a reading of 9c before starting & it seemed to read fine while warming the car up it reads 90c when the dash reads 90c so looks ok..

there are no fault codes flagged by vagcom other than abs sensor so im a bit baffled tbh, the car has had an intermittent misfire on idle since I got it & I have changed plugs from Bosch to Ngk platinums, the leads to dub power 7mm items & the coilpack for a new beru item the old one says Telefunken & is date stamped 96 so was prob the original...changing those items made it pull harder but made no difference to the miss fire on idle so I forgot about it as it dont seem to miss fire anywhere else in rev range..

the misfire when cold seems to like an extension of the missfire on idle but its hard to say, I was thinking fuel pump relay but looks fine under a magnifying glass & surely it should misfire all the time if it were the relay?

I swapped the coilpack back to the old one last week & that made no difference even swapped leads to my old ones & tried combinations of old & new lol makes zero difference so cant be on the ignition side it runs normal once coolant is 90c... think im gonna try new temp sender for ecu & fuel pump relay tomorrow has anyone got part no for the ecu temp sender its the one on the left out of the 3 on front right of the block right?

edit: I have a log from when its not doing it & one from when it is doing it if anyone wants to see? I cant make much sense of it tbh lol

edit2: looks like vagcom is reading the blue temp sensor not the yellow one for the ecu..with the yellow sender unplugged the car idles high but does the same miss fire thing so Im gonna change it tomorrow & see if that makes it better..very much doubt it will tho.

[kniterider 0]

im not much help but had a prob with mine for a while last month, i was lead to believe the blue 2 pin sensor was the one which told the ecu the temp of the engine, the other does the gauge on the dash and im not sure what the other does, i changed mine and it made no difference to my prob as mine turned out to be the maf sensor that was giving me probs...

[rodney 17]

Whilst I am sure you have looked at these I will post in case

Misfires are nearly always due to 3 things

Spark

Air

Fuel

Daft as it sounds... are your plug gaps correct. The fact that it has to heat up indicates that there is something expanding to allow correct operation.. If you can get someone local to loan you a working lead/coilpack then you know they work. It always possible to replace a broken part with a broken part

Air, is everything sealed where it should be. Is the air filer clear and flowing and MAF/sensors etc ok

Fuel Is/are the filter/injectors blocked (partially)/ regulator in anyway and do you have sufficient quantity of the correct fuel in the car or is there a leak local to the injectors etc..

I hope it helps and heads you in the right direction