94 Jeep Grand Cherokee Loredo Rough Idle

[LELeach]

My 94 Grand Cherokee has the 4.0 in-line six. A couple of weeks ago it started missing and running very rough at idle. I replaced the plugs, wires and distributor cap. It still idles very rough. If I increase the rpm by 200 or so it runs smooth. Could it be my power brake booster. I am getting ready to replace it and I thought maybe the vacuum could be leaking through the diaphram. Any ideas? Also where can I find a step by step how-to on replacing the booster.
Thanks, Larry

[2BitJive]

Clean your throttle body and IAC sensor. I did this and my idle improved 100%. Just pull the air cleaner off, open the butterfly valve and spray some carb cleaner in there. The sensor is on the back-side of the throttle body near the manifold. Its held in place by 2 torx screws. Pull it out and clean with brake fluid or wd-40, reconnect and you should be good to go.

[LELeach]

Originally Posted by LELeach

My 94 Grand Cherokee has the 4.0 in-line six. A couple of weeks ago it started missing and running very rough at idle. I replaced the plugs, wires and distributor cap. It still idles very rough. If I increase the rpm by 200 or so it runs smooth. Could it be my power brake booster. I am getting ready to replace it and I thought maybe the vacuum could be leaking through the diaphram. Any ideas? Also where can I find a step by step how-to on replacing the booster.
Thanks, Larry

2BitJive, Thank you very much for your help. I did what you told me to do and it fixed the problem. I really appreciate the help.
LEL