Rpm Varies Witing 2secs.. + Coughs/splutters At Higher Rpm

[Blood]

G'day all..

New to skylines, long story short-- I picked up a gtst 4-door R32 for a bloody bargain.

Problem #1-

After warm up & little drive, the Revs will vary between 1200-2100, and it is constant changing. Within 2 secs it changes, like im tapping the accelerater peddal. I've look around and cant seem to find a problem like this on the forum.

It is an Auto RB20det, annoying, if i pull up (& take it out of Park) the thing sits there like im whacking the peddal, makes everyone look--- like im some kinda hoon Please help.

Problem #2 (and possible connected to #1 problem)-

The car accelerates fine, great in a way, but sometimes it feels like it boost spikes. About 5000rpm or along the way up to 5000rpm, the car jumps, coughs,splutters ect..

I was thinking boost spikes.

The car is pretty well stock at the moment. so if i floor it it most of the time hesitate and splutter like mad.. possible backfiring.. - please help on this too.

I adjusted the RPM idle screw to try and get it lower, because as driving and approaching a red light, the brake had to be pressed a bit harder.. compared to other autos i drive. You can feel the force on the brakes , as if i still was applying the accellerator a little..

Cheers in advance. (oh, i also replaced the AFM) the problem was a little better, but still playing up... not much diff really.

[BoyWhoCriedWolf]

Check for any boost leaks. Like a hose off or a vac line off. Check coils as well.

[mad082]

the lumpy idle is probably being caused by a dirty IAC. do a search on here of how to clean it.

as for the splutter up in the revs, it won't be a boost spike (but getting a boost gauge will tell you for sure), but i'm guessing it is a coil pack or spark plug problem. most likely coil packs though. you could start by replacing the spark plugs as they are cheaper the coils. just get some NGK BCPR6ES plugs from your local car parts place. see if that makes it any better. if it doesn't then invest in a new set of coils

[Blood]

Thanks, the more I think it could be air leak or over boosting somehow.....

However, I bought a set of coil packs.. And plugs bcpr6es. Will fit the stuff tonight.

Also thinking about cleaning a few things while I take them off for the fitnent of coils ect,,,,

I just really hope it fixes the prob. I didn't mention that under no load (neutral) it will rev with no probs

if coils and plugs don't work ,,, what is next ??

[BoyWhoCriedWolf]

Does the car make any boost at all? Hunting (idle up and down) is a classic sign of an air leak.

You could be getting spark blow out, this will happen with crappy plugs/incorrect gap/coils. This happens when the car starts making the higher levels of pressure.

[Blood]

Yeah it boosts... the problem is hardly there when its cold (cold air)

I fixed the idle up / down problem so far... although it idles at 1700'ish when warm. (about to clean AAC valve)

Its just the missfire/boost spike/ splutter thing now..t

(thanks guys big help and support)

[Blood]

Update ---

Fixed 99.9% of all problems.

I replaced the coils, and plugs...

----> LMFAO @ plugs <---- looks like they are original.. !!!

(ignore dirty/grubby fingernail :lol ) (the web-cam doesnt show proper quality of the metal. Its really chalky-white, like a burnt out cars engine block)

I also cleanded the AAC valve thingo, made a good difference. Not multi-rev level, no splutter/spikes ect..

Only problem i have now is the RPM is about 1200.

I cant seem to get it lower. Quick thoughts ?...

Might come good after i do an ECU reset...

and is there any kinda DIY to set the TPS to the correct position ?.

Edited May 8, 2010 by Blood