I have a 95 Jimmy that has devoloped a really rough idle. My mechanic found that the brake booster was shot so we replaced that hoping that would fix the problem, the truck runs way better but still has a really rough idle. The only thing I can think of would be plugs and wires but the truck runs really well when you're driving, its just the idle thats bad. Anyone have any ideas?

 

You can check the wires at night with a spray bottle of water. Mist the wires and watch for a light show. If they are leaking spark, you'll see some nice blue lights!

As far as plugs go, Pull a few from both sides and check the condition and gap. They should be a somewhere between whitish-tan to tanish-brown.

 

Just wanted to say that I got it fixed incase anyone was interested.

What turned out to be the problem was that a chunk of carbon got stuck in the egr valve holding the pintle open, thereby causing a rough idle. My mechanic just took the egr out, picked the chunk of carbon out and cleaned it up with brake clean and while it was out fired the motor up and revved it up a bit. Turns out chunks of carbon shot out of the hole where the egr valve sits so I guess the carbon buildup in my intake was pretty bad lol. Anyways, he reinstalled the egr valve and my truck runs better than ever. Now I just gotta figure out why my 4wd doesn't work...

 

Try Seafoam. Itll clean your intake track real well, get em at AUTOZONE for under 5 bucks a bottle.

 

Glad to hear you got it running good.

On that 4x4, hmmm.....bet its either the electric motor that engages the front axle, or if that is working, could be the automatic hubs. I scrapped my auto hubs 2 winters ago and installed Warn locking hubs, I didn't even realize the 4x4 wasn't working until I got into some big snow and gunned it and she was a little slow accelerating. Turns out most of the time the rear posi in my truck was taking care of business most of the time. Provide more detail about your 4x4 problem maybe we all can help you track it down.