rough idle on my vt any ideas?

[Giant]

Could be faulty fuel pump or dirty fuel filter if it goes away when you start driving and is only on idle

 

[SavVYute]

(1) I'd have a look for a disconnected or split hose somewhere.
Can you hear anything hissing slightly in the engine bay?

(2) Could be a dirty throttle body. Give it a spray and wipe out with throttle body cleaner.
That will help too if it is the idle air control valve (IAC) sticking.

(3) Your throttle position sensor (TPS) might be sticking or it could be dodgy.

(4) Put a new air filter in and see if this makes a difference.

(5) Did you fit the correct spark plugs NGK-BPR6EFS-15 and are they gapped correctly? 1.5mm.

(6) Fuel filter

Try all the cheapest options first though.

 

[WhisKiz]

Had Similar Problem

I had a similar problem and funnily enough it turned out my cats were blocked.. (catalytic converters)

 

[CHA53R]

Check codes, might be the answer in there if not clean MAF, change plugs and leads then see how it goes, if runs fine fir a little while and does it again change coil pack.

 

[cmarico]

Had the same problem. Check the Purge Hose under the throttle body. Mine had come undone and gave me a rough idle and slight hiss. Plugged it back in and zip-tied it on, and running perfectly. Takes 10 seconds to check and nothing to fix.

 

[VT_FREAK]

**NEED SOME ADVICE PLEASE**
I have a 1999 vt commodore, there is a problem with it that has got me stumped? The engine light is coming on it has a lost of power, a tiny bit of back fire? And sluggish gear change.. I have replaced new spark plugs/spark plug leads, new oil, also new head gaskets/valley cover gaskets/rocket cover gaskets as well... But still having the same issue PLEASE HELP!! thanks in advance :spot on:

 

[DLFHUB666]

If the engine light is on there will be a code logged in the system. search this site on how to read codes then get back to us.

 

[Tsunamix]

Hmm...shorted knock sensor would do this.

Perhaps also a Cam position sensor.

 

[Nut Kracker]

A faulty Throttle Position Sensor (TPS), will cause the engine light to come on.

Check for error codes.
https://forums.justcommodores.com.au/threads/checking-error-codes-vt-vx.23665

 

[VT_FREAK]

i have found a slight oil leak i got told that it could be the head gasket slipped. can this happen?