Rough idle in drive but only when sitting at a stoplight

[Bob Barker]

Maybe have someone hold the brake pedal down in the drive way while you listen around under the hood or chassis or wherever the source of noise is.

[Mile High VX]

Maybe have someone hold the brake pedal down in the drive way while you listen around under the hood or chassis or wherever the source of noise is.

Make sure that they like you if you choose this option...

[etlsport]

Mine will not cure right away when I turn off the ac but like earlier today I stopped at a light and had an awful idle. Switched off the ac and nothing happened. I idled forward when the light changed but still missed the light. When I stopped it was idling perfect

[Marlin]

If it is pronounced through the brakes, I too would tend to lean toward ABS, but then the light would be on. The fuse is under the hood, clearly labeled on the fuse diagram. That will have no effect on your vehicle other than no ABS and light on in the dash display. I pulled my fuse long ago...

[tom4bren]

If it is pronounced through the brakes, I too would tend to lean toward ABS, but then the light would be on. The fuse is under the hood, clearly labeled on the fuse diagram. That will have no effect on your vehicle other than no ABS and light on in the dash display. I pulled my fuse long ago...

I was just thinking that if the ABS is 'confused' it may try pulsing the system whilst at a full stop, causing the vibration. It's a long shot but easy to check out by just pulling the fuse.

[vt_maverick]

It's a long shot but easy to check out by just pulling the fuse.

That's great, but which of the two fuses is it (see question above)?

[circmand]

That's great, but which of the two fuses is it (see question above)?

pull them both or pull one then the other either way it tests the proposed problem. Have you given considerationof stopping by a brake place and letting someone wo can see and hear the problem make a suggestion? After all diagnosis by description is quite difficult . BTW dont rely on not seeing the light it may be burnt out.

[tom4bren]

That's great, but which of the two fuses is it (see question above)?

"Quit changin the subject and answer the fookin question"

My favorite quote from Braveheart - ya gotta say it with a heavy Scottish accent.

[vt_maverick]

Which fuse is it? Looks like there are 2, one a 20A and the other a 40A:

[RickOKC]

Hmmm, I wonder if this was my mystery sound. Soon after I got my VX, I noticed a very low frequency sound/vibration when I was in gear with the brakes on. In fact, it reminded me of the sound brakes can make sometimes when you creep forward. Maybe it was the last dying gasp of the ABS. It took a few days but the mystery sound eventually disappeared.

[etlsport]

You can also try pulling the e brake while topped and releasing the regular brakes to see if that makes a difference. mine was plenty strong to hold me in place. Alas didn't do a thing for my rough idle though

[vt_maverick]

Just trying to do a little pre-diagnosis so I can determine if I need to start working on finding parts. I'm really not a big fan of being out of a car for a day only to hear that they couldn't get the part they need so I've got to go back, order it through Isuzu, then repeat the process again next week. The research paid off with the neutral safety switch issue, so I was just thinking the same way here.

We're going to be out of town for the holiday but I believe my garage is open Friday. I might drop off the VX Wednesday afternoon and let them keep it through Saturday since it doesn't impact my commute or anything.

[vt_maverick]

Update... I shut off the A/C on the way to work this morning and had no problems. Flipped it on at the stoplight just before our parking lot and the sound came right back. So does that change the diagnosis? I haven't pulled the ABS fuse yet, probably do that on the way home.

[Bob Barker]

Update... I shut off the A/C on the way to work this morning and had no problems. Flipped it on at the stoplight just before our parking lot and the sound came right back. So does that change the diagnosis? I haven't pulled the ABS fuse yet, probably do that on the way home.

That makes me think it's a vibration somewhere. If the load on the engine changes and makes the noise come and go then I immediately think vibration. It's still a free check to pull the ABS fuses and then test for vibrations with/without a/c.

[vt_maverick]

UPDATE: While the shop was trying to find the electrical gremlins in my fog lamp, I asked them to also track down the source of the vibration. Apparently it's being caused by the exhaust pipe rattling against the Kilby skid plate, so they checked all the hangers and found that everything was tucked up tight like it should be. They told me that there's like a 1mm clearance between the pipe and the plate at off/idle/park, but that the slight vibration associated with being in drive is causing it to contact. It's probably happening at speed too, but it's more noticeable when you're sitting still. They suggested cutting a hole in the plate to eliminate the rub, which I thought was a good idea given this problem and the concerns that Sue, I, and others have had with the potential for significant heat build-up with the Kilby plates. I'll take a pic when I get it back so you guys can see what was done.

Can't wait to pick it up to see how much better it drives/stops!