idle problems!?

[SunnyTk]

I have just purchased a 1995 Infinity Q45 for pretty cheap, and its idle stumbles around 1100-400rpm... and it puffs out grey smoke... also, once in a while when you rev it, it stalls out when its dropping down.

could it be the maf? or is it some other huge problems with the grey smoke?

Any help would be greatly appreciated!

[elwesso]

How is the fuel pump? does it make noise?

Thats always the first thing I check on old Q45s... People like to blame other things but fuel pumps are the first thing to check always... IF you can listen the fuel pump (from the trunk) when you're idling the car it should make essentially no noise.. If it sounds like its buzzing (like a beehive) then its bad and you need to replace it...

Check that first.

[freedomm60]

I agree it sounds like a fuel issue. You may want to check the idle air control valve which controls idle. Some times they stick or become clogged with dirt.

[SunnyTk]

Thanks for the help!

Ill check the IACV first. can somebody please tell me where it is on the vh?

[Infinitiguy19]

This is one of the best writeups for removing the plenum: zer...tures.

And there are many things that can cause Idle problems: http://q45.org/roughidle.html.

And to add check the Injectors when they are cold (Car sitting for a day) and hot (After fully warmed up and driven).

Check for any vacuum leaks.

And check your spark plugs.

So to sum up:Injectors/Fuel pumpAir (MAF, AAC Valve, Vacuum leaks)Ignition (Spark plugs) (NEVER THE COIL PACKS AS THEY ARE BUILLIT PROOF on the G50 (90-96 Q45's) that can't be said for the FGY33 (97-01 Q45's)

[Kiven422]

Check the wiring for the MAF throttle body... I had to repair it on my BLK Q45 a couple months ago... as changing the MAF would not fix it.

I just started having that issue on my WHT Q45... right now the car runs fine because i twisted the MAF wire so theres no short circuit.

Both cars would turn off soon after you start it or rev it.