wakony

Hey everyone,
I have been searching the forums and found several posts about this problem and I have attempted several solutions. I have to drive to Colorado from Georgia in this thing in two weeks.

My 88 Cherokee is currently idling rough and after a good drive, will die when coming to a stop.

My mechanic buddy and I have looked it over. I have checked for vaccume leaks, put seafoam through the booster line, and cleaned the idle control.

I have brake pressure and they work fine and there is pressure in the brake booster line. However my question are,
why does the engine idle fine when the brake booster is unplugged?
Any ideas on how to make it idle normal and not die when I come to a stop?

cruiser54

Tighten up your intake manifold bolts. Spray along the intake manifold and throttle body to check for vacuum leaks. Use an oxygen sensor safe carb/throttle body cleaner.

Radi

Does it stall when you step on the brakes? Even when parked?

Cherryokee

Remove and clean your Idle Air Control (IAC) Valve and the bore with Throttle Body Cleaner. Do not turn or manipulate the pintle on the IAC. Clean the throttle body as well.

Removing the booster vacuum line allows the unported vacuum to draw free air to the manifold thus compensating for the blocked IAC port. That's why the idle seems to improve when you disconnect that vacuum line.

wakony

Radi- it will only stall after a drive and never in park.
Cherryokee and cruiser - Thanks ill try that stuff today

wakony

My mechanic buddy thinks it is the booster? Any thoughts?

cruiser54

Could be. But I'd do the stuff we recommended anyway because they are known issues.

Do your brakes work effectively?

wakony

The bakes work fine that's why I doubt it

cruiser54

I would doubt it, too then. Maybe something's messed up in the MAP.

wakony

So u cleaned the hello out of the sensor and throttle bodyand ran another can of seafoam through the vaccum. It idled like a dream, however.I still lost power after a 20 min drive... At the gate to my apartment when I applied the brake. What is a map

cruiser54

MAP sensor is located on the firewall right behind the engine. Has a vacuum line to it and a wiring plug. Follow the vacuum line down to the throttle body. It can't be messed up at all. No cracks, melted spots etc.

Have you sprayed for vacuum leaks as suggested earlier or tightened the intake manifold bolts?

tgordon

MAP=Manifold Absolute Pressure
It feeds info to the ECU which calculates how much fuel is needed for proper combustion.
My bet is on a vacuum blockage not a leak. I would replace hoses one at a time until prob gone or all replaced. If prob still present move to next trouble shooting step.
I find trouble shooting the most frustrating part of most repairs. I love when there's a bullseye on the problem.
Sometimes the questions we ask are more important than the answers to them.
Ask the correct questions and receive the correct answers. We hope.


Man asks boy, "Why are you draggin' that chain up the road?"
Boy replies, "Mister, you ever tried pushin' one up a road?"

Radi

You might check to see if your brake booster is leaking vacuum, even though the brakes are working fine.

wakony

So I thought the problem was fixed because cleaning the throttle body and all of those components cleared up the rough idle so drastically. However it is not the case. Stalled at a redlight this morning.

When I cleaned the idle control I dropped the part. Could that have damaged it to the point of not working? I checked the MAP and the vaccume line isnt cracked or anything.

I have a sub in my jeep. Could the amp be sucking too much juice from the battery and making it die like that?

Also, could the brake booster be dirty? I know it might be a dumb question but this is really con-fuddling me.


Edit: Cruiser, I tightened the bolts, what kind of spray should I use to check for leaks? Should I use an unlit butane torch or something?

XJSport1986

I had the same problem I changed the tps that fixed mine rough idle stalling when stopping