Vs caprice v8 losing power at high rpm

[baaj]

Hi all, new to the forum here. Thought id kick it off by asking for some suggestions or if anyone has had the same problem iv been having for the past few months.

The car is a 99 vs caprice series 3 v8. has 200k+ km on the clock but its been in my family since new and has always been looked after. Lately iv been noticeing that im losing power on and off at higher rpm (4k+). I was thinking the fuel pump might be getting on a bit as its never been changed. Had a fresh service about a month ago but still having this annoying problem. Motor is standard. Being a series 3 it has the updated 5.0 litre as most of you know.

Any suggestions would be much appriciated.

Sam.

 

[baaj]

Bump......?

 

[Brett_jjj]

Try doing an error code check.See if anything turns up.Heres a link that tells you how to do this test.---https://forums.justcommodores.com.au/threads/checking-error-codes-vr-vs-revised.22307---If you scroll down near the bottom of the posts in the link,there are some excellent pictures that shows you how as well.

 

[1SIKR8]

check small things, may be a stupid question but when was the last time the fuel filter was changed ... when u say loosing power .... do u mean like it struggles to rev .... ? may be stupid questions ( im sorry ) but it does help out

 

[baaj]

I'll check out the error code stuff.

Yeah strugling to rev, not electrical wise. Sort of an un even power curve if that makes sence? Not cutting out or mis fireing, it feels like its losing about 20 kw after about 4k all the way to redline. Sometimes it will only do it for a split second. Sometimes it wont do it at all!? The weather doesnt seem to make a difference. Car has always used premium.

Thanks for the replys.

Sam.

 

[baaj]

Came up with 35 & 43, Could knock sensor have something to do with it?

 

[Brett_jjj]

Code 35 is idle speed error. The IAC (Idle Air Control) valve cant control the idle speed.And code 43 is knock sensor fault code.Check the wiring to the knock sensors and check the IAC wiring as well.If the wiring looks ok then maybe try replacing the knock sensors and the IAC valve.You can clear these error codes by disconnecting the battery for a couple of minutes.Try clearing them and see if they come back again before doing anything.The IAC error can also be caused by a vacuum leak around the engine.Theres a vacuum reserve tank under the left front guard,it looks like a black plastic ball thing.Check that it is ok and that the vacuum hose going to it is not broken or has been disconnected.Also check the vacuum hoses around the engine bay for splits,cracks or disconnected hoses etc.

 

[hako]

Brett - I seem to remember reading somewhere that if the knock sensor fails the ECU uses a default setting for max spark advance ..... which would cause a lack of power. Does your Tech1 data mention anything about this?

 

[baaj]

Took video of it, Might be abit hard to tell but i could definatly feel it at around 4700 to redline.
Im probably getting annoying now so il just take it to a mate to have a look at it.
If nothing else enjoy the chirpys!

Thanks again for replies.

Sam.

 

[bandit10]

That sounds alright to me maybe your worrying about nothing?? or maybe it just doesn't show to well in the video
From how i understand knock sensors on the 5ltrs, if they detect a knock in the engine, or become faulty they will retard the ignition timing 10degrees to safe guard the engine.
Yours sounds to be running fine though in your video.
nice chirps