VS auto first start everyday idle drops right down when put in reverse?

[Holden chik]

Every morning I start my car revs drop right down when I put in reverse & nearly stalls sometimes. Idle has not been smooth for many months now though, just a little bit off, was thinking TPS but now thinking maybe IAC? And when I reverse out my driveway & then put in drive it usually takes a few seconds before gear actually goes into drive..
The idle was already not quite right but got worse after throttle body was taken off, has been taken off since & tried another one but no difference. Idle did improve a lot after valley gasket done earlier this year but still not quite right.

 

[vs-lover]

Sounds like a vacuum leak, try looking at your tubes that go between your engine and charcoal canister next to the radiator on the RH side.

 

[Immortality]

the TB/IAC would be the first port of call, vacuum leak as suggested above the 2nd. I'd also consider looking at the ignition and check the base timing etc. Depending on the age of the components I'd recommend starting with a new rotor/cap, leads/plugs and possibly even a new ignition coil. Check the base timing is set properly at 10°BTDC (before top dead centre) and then see how things go.

 

[BlackVXGTS]

Every morning I start my car revs drop right down when I put in reverse & nearly stalls sometimes. Idle has not been smooth for many months now though, just a little bit off, was thinking TPS but now thinking maybe IAC? ....

The only time I had a similar problem (also intermittent) in my 383 VS Calais, it ended up being TPS related.

 

[losh1971]

Id replace the TPS as it can also cause stalling like you mentioned in another thread. It will also affect gear changes if you have an auto.

 

[Deuce]

Trans oil level okay in it??

 

[Holden chik]

the TB/IAC would be the first port of call, vacuum leak as suggested above the 2nd. I'd also consider looking at the ignition and check the base timing etc. Depending on the age of the components I'd recommend starting with a new rotor/cap, leads/plugs and possibly even a new ignition coil. Check the base timing is set properly at 10°BTDC (before top dead centre) and then see how things go.

Hey, I have replaced quite a few things earlier this year including dizzy, rotor button & ignition coil. Also did plugs not long before that. Have not done leads yet.. Will look into your other suggestions. Thanks

 

[Holden chik]

The only time I had a similar problem (also intermittent) in my 383 VS Calais, it ended up being TPS related.

Hey thanks, did take it to mechanic the other day & he did mention OBD showed TPS voltage low, I had been looking into replacing it for a while but was told it was $120 so started with replacing the cheaper things first, I have now just found Supercheap sells TPS for only $37 so ordering that today & will give that a go.

 

[losh1971]

Make sure it's a Fuel Miser brand as FM is rebadged Delphi but cheaper. Anything else might fail fairly quickly. Spares Box online has Fuel Miser ones for about $37.

 

[Holden chik]

Make sure it's a Fuel Miser brand as FM is rebadged Delphi but cheaper. Anything else might fail fairly quickly. Spares Box online has Fuel Miser ones for about $37.

Ok great thanks for that