Engine Shuddering. Need Help

[phoenix88]

HI guys,

Im asking this on behalf of a friend. She just recently bought a 99 skyline GT 4 door. The car was running fine when she bought it last month but now have develops what could be described as a shudder.

The car seems to shake when the revs are low and sometimes conks out when idling. Also sems to have lost a bit of power. Any help with this issue would be much appreciated.

Cheers

[starwarz]

I had a similar issue when i bought my 99 non turbo, at the lights the engine will shudder but go away whilst driving.......mine went away when i put in some some fuel injector cleaner and put nothing but 98 petrol.

[phoenix88]

I had a similar issue when i bought my 99 non turbo, at the lights the engine will shudder but go away whilst driving.......mine went away when i put in some some fuel injector cleaner and put nothing but 98 petrol.

Ill give that a go. Found out that the car was run to nearly empty maybe it could have some sediment gone through the system or just dodgy fuel. Might try to drain the tank.

[AYW550]

how did you get on with the injector cleaner?

mine just started doing this also, - ive been thru the whole coil pack problem and this issue feels much different to me - after a long road trip my car now likes to 'shudder' while idling, but it only seems to start doing it after driving for about 10-15 min after it really warms up, you can really feel it sorta thumping the back of the drivers seat thru the exhaust, yet the engine runs perfectly smooth and rev needle doesnt move. engine light has not come on yet. sometimes when its bad enough it will also struggle to accelerate under throttle, but seems to go thru patches in the rev range where its nice and smooth but then sputters.

about 30km before the problem started i had just filled up my tank from the 1/4 mark and wonder if i got sum dirty/old gas???

thanks.

[starwarz]

I dont think you guys have a coilpack problem considering there is no engine light that should be on to indicate this, even if the petrol injector cleaner does not work it does not hurt to throw it in....my mechanic does it to all the cars he servies and reckon its helping to a degree.

[MissR34]

best to start a process of elimination.......start with the basics (and interesting enough youd be suprised how many problems can be the simplest of things)....but good luck anyway

ps carby cleaner is good stuff too......

[R30forasong]

Just go and check your fuel lines as well. my r30 needed a bit of a pumping cos it was sitting a while low on fuel. maybe? just maybe?

[Duchie]

Well if you're getting idle hunting when not using the accelerator it's your aac valve, theres a tutorial on how to clean it out. Here it is http://www.skylinesaustralia.com/forums/topic/110431-diy-aac-valve-cleaning-idle-reset/page__hl__diy+aac+cleaning

I find on my r33 that because of my faulty cam angle sensor the timing jumps out and the car feels strangely underpowered in some of the rev range but this problem is intermitant. I took my injectors out and had them professionally cleaned, guess it cant hurt to get it done.

[SKITTLES]

I dont think you guys have a coilpack problem considering there is no engine light that should be on to indicate this, even if the petrol injector cleaner does not work it does not hurt to throw it in....my mechanic does it to all the cars he servies and reckon its helping to a degree.

The "Check Engine" light won't come on for coil-pack issues.

Steps to fix this problem:

• Run shell V-Power (My R33 has a Shell Premium sticker on the fuel tanker.. can only assume they want me using shells premium petrol)
  
• Run an injector cleaner (wynns spitfire, for instance)
  
• Pull each spark plug out and have a geez at it; are they browning badly? YOu may need to change them.
  
• If your spark plugs are functioning fine, it could be a coilpack issue. Check over them for small cracks or damage. I've personally covered mine in silicon which has slightly assisted with my misfire issue.
  
• Have you washed the cars engine bay recently?
  

The AAC valve sounds interesting.. I'll have to do a bit of research about this.

Edited June 29, 2011 by SKITTLES

[calebR33]

If what you mean is when your rpm suddenly drops... stalls... almost as if your fuel is suddenly cut CHANGE THE AFM NOW!