Rough Idle

When I bought my G (a '99), I loved the way the engine quietly purred. Now (at 40k miles), it seems to sound a bit rough. And when I start it, it idles hard. When I took it in for a check up about a month ago, they said that they noticed the hard idle, and I should have my injectors cleaned (for only $149). I thought that by running some high test, and trying a few fuel injector cleaners in my tank, that might fix it. Well, it didn't. So, should I pay the $149, or does anyone have any other ideas to bring back that smooth quiet purr....thanks!

Injectors usually never go bad, I wouldnt waste your money on this.

What I would have done is have your throttle plate/body cleaned out. This usually tends to gunk up from the EGR recirculating exhaust gases back into your intake. This may free up your idle problems.

Also check your base idle setting. This may need a reajustment.

How many RPMs does your idle jump around?

When you talk about rough idle, does that mean the car is vibrating?

When I say "rough", I mean that the engine noise is much more noticable, and the car is rattling more. When I'm driving, and come to a stop, it's a bit quieter. It just seems to be worse when I'm in park, idling. Any ideas...

I once had an auto that rumbled/rattled in neutral and park but not in gear. Turned out that the flexplate bolts were loose.

Might be a red herring, but if they are loose then it will be much cheaper to tighten them than to have the flexplate shatter ... as mine did. :(

You have to check the AAC valve
this may be your problem

i think i have the same problem. when i start up it tends to idle rough but once warmed up it goes away. but now there is a new sound to the mixture. when i start my car for the firt time in cold wether i hear a weird noise for like 1 second. it kinda sounds like. hmm let me paint a picture if u guys ever hear a vacum that get stuck on something that wont get sucked up it kinda make a weezing noise. wondering if that is normall sound for the g20.

dam g20 are filled with little irritating noises

Originally posted by apintojr
when i start my car for the firt time in cold wether i hear a weird noise for like 1 second.

Its the HVLA pumping up...dont worry about it, its normal.