VY2 idle issues

[chaostommy]

I bought a vy2 Calais at the end of last year and think I might have picked up when old mate sensed things were gonna go down hill so sold it to me. It's a 3.8sc (l67) running 10lb. As the guy before me did these following mods I don't know fact from fiction although he did show me receipts.Basically the motor is rebuilt with forged pistons, aftermarket cam, bearings, high ratio rockers# Cold air intake and Mafless tune + modular pulley on the blower, pacemaker extractors and the full exhaust. It goes nice but as soon as you back off the gas the idle drops right down to nearly stall! Rolling down a hill it just bounces between 500rpm and up to say 1500rpm without touching the gas. So far I've replaced alternator, iridium plugs and leads but not coil pack and replaced fuel filter. The whole maf less tune to me looks like it was a case of cut some wires off and go for broke. Any ideas guys?

 

[pjdm1980]

Sound like it would have some get up and go with those mods, I know the bloke that brought my old S/C Stato told me he had the same type of issues as yours and it turned out to be a weak coil pack.

 

[Goon]

My old man had a ford with a similar issue, turned out the computer needed a tune up. But like you said you havent replaced the coil pack.

 

[chaostommy]

Coil pack was my guess... Thanks guys

 

[Dr HaxZaw]

check your Idle Control Valve... it sits on top of the throttlebody
i had the same issue and once i cleaned it out problems solved... that being said if the engine has been rebuilt recently i dunno whether it would be dirty but better check anyway

 

[BWNVY2]

this is common for L67 with boost mods. its just rev hunting. it can be fixed by a slight turn of the idle screw or mapped out in a tune. i used to have the issue with my old L67 intercooled. Hope that helps

 

[DevilDRake]

^^ agreed, My car did the same thing on the tune, needed to adjust the idle screw in the throttle body, otherwise get it retuned.