VN S1 Running Problems

[F/INJ Suicide Machine]

Hey guys. Got myself a VN S1 HSV Enhanced SV20. Drives very well, except for one thing. On idle the revs aren't going crazy but they are a little up and down. Also when I hold the revs up at about 1500-2000 the car misses and fluctuates rpm. Driving normally its a rocket and you wouldn't know but it annoys me it runs rough. I've replace DFI, coil packs and leads/plugs. New oxy sensor. What could be my problem??? Thanks

 

[Jxfwsf]

it's a vn s1, hence why the cam & plenum were changed in the s2 engine amd the plastic bellmouth was added to the intake

 

[F/INJ Suicide Machine]

Surely that's not going to cause a miss like that. I understand the fluctuating idle but the miss sounds eclectronic.

 

[IRON8]

Surely that's not going to cause a miss like that. I understand the fluctuating idle but the miss sounds eclectronic.

not always, could be a worn lifter or worn cam, is it a bit rattly when cold? how many ks? a worn lifter would cause both rough idling and a miss but it would go clack clack clack at idle

 

[F/INJ Suicide Machine]

It's only got 220k on the clock. It's pretty quiet apart from the alternator bearings. Could it throttle body/ sensor related?

 

[IRON8]

have you cleaned out the throttle body?

 

[F/INJ Suicide Machine]

I cleaned a spare one I had and that's on there so yes.

 

[IRON8]

vacuum leak or dirty injector. try running a bottle of injector cleaner through it, no great loss if it doesn't work..

 

[F/INJ Suicide Machine]

Yeah I'll try it. Just seems so random. It's not in time with anything and had no rythem. See if I find anything...

 

[hi_ryder]

check you map sensor dosent have a vac leak. when you did the throttle body did you remove and clean your IAC sensor? they sometimes get clogged with carbon and can cause the rpm hunting symptoms your getting.