[mrussell]

I have a '99 Astro w/118,000 mi and runs well, with the exception of an annoying rough idle in drive gear. It idles fine in all other gears and does not stall or die. I thought at first it may be a vacuum leak, but found nothing. It has about 14,000 mi since it's last tune-up, but as I said before, it runs and drives fine. PCV and EGR have never been replaced, but cat only has about 1k mi. Kinda lost after checking the basic, obvious stuff. :think: Any guidance would be appreciated. Thanks in advance. :thumbup:

 

[astro355]

Hello,

is it setting any codes? Have you had it read?

The EGR can cause this type of problem. Usually a good inspection and cleaning can help.

 

[mrussell]

Okay, took awhile to get back, sorry :shifty: . No codes or engine light and like I said before it only does it in drive. It's not massively rough idle, but it is noticeable. Took off EGR and cleaned w/wire brush and compressed air, it helped a little, but not significantly. Any ideas of where to look next??? :think:

 

[davesyo]

Take off the IAC and clean it and clean throttle body . See what happens

 

[astroturf]

Have you cleaned the maf yet? Jim

 

[$uperJoe]

on the other side of potential motor codes and failed monitoring devices i would look at the motor mounts. especially the drivers side. look for worn or loose rubber and shift in the motor side to side when the brake is applied firm and some to none throttle pedal is applied

 

[astro355]

on the other side of potential motor codes and failed monitoring devices i would look at the motor mounts. especially the drivers side. look for worn or loose rubber and shift in the motor side to side when the brake is applied firm and some to none throttle pedal is applied

Worn/bad motor mounts will only make a rough idle seem worse. Bad motor mounts could be an effect of a rough idle but bad motor mounts will not cause a rough idle.

 

[$uperJoe]

just throwing other fairly simple to check free pieces of advice for those that may not think to check there. some think they will only go out if there is an engine problem and forget that they are torqued against every time acceleration is applied. also if there is an oil based fluid leak they will absorb the oil and fail premature even if the engine runs perfect

 

[astro355]

just throwing other fairly simple to check free pieces of advice for those that may not think to check there. some think they will only go out if there is an engine problem and forget that they are torqued against every time acceleration is applied. also if there is an oil based fluid leak they will absorb the oil and fail premature even if the engine runs perfect

I completely agree. But bad engine mounts don't cause rough idles, rough idles cause bad engine mounts.

 

[Gary]

just throwing other fairly simple to check free pieces of advice for those that may not think to check there. some think they will only go out if there is an engine problem and forget that they are torqued against every time acceleration is applied. also if there is an oil based fluid leak they will absorb the oil and fail premature even if the engine runs perfect

I completely agree. But bad engine mounts don't cause rough idles, rough idles cause bad engine mounts.

x2 with 355. :goodpost: