rough idle
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Junior Member
Joined: Feb 2011
Posts: 54
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From: arizona
Year: 1993
Model: Grand Cherokee
Engine: 5.2 318
Originally Posted by Bustedback
There is no MAS on our Jeeps. MAS stands for Mass Airflow Sensor, they measure the amount and temperature of the air going into the intake and are usually located down stream of the airfilter. Our Jeeps have MAP sensors, that stands for Manifold Absolute Pressure. It measures engine vacuum and sends the signal to the PCM to let it know how much load is being put on the engine.
Junior Member
Joined: Jan 2010
Posts: 76
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From: Crawfordville, Florida
Year: 1993
Model: Cherokee
Engine: 4.0
There is no MAS on our Jeeps. MAS stands for Mass Airflow Sensor, they measure the amount and temperature of the air going into the intake and are usually located down stream of the airfilter. Our Jeeps have MAP sensors, that stands for Manifold Absolute Pressure. It measures engine vacuum and sends the signal to the PCM to let it know how much load is being put on the engine.
lol
Junior Member
Joined: Jan 2010
Posts: 76
Likes: 0
From: Crawfordville, Florida
Year: 1993
Model: Cherokee
Engine: 4.0
i would say the first thing to do is fix the vacuum leaks, then go about cleaning the sensors, go ahead and knock down the easiest first. then you can take the injectors out and clean them if needed along with the spark plugs. also you can check the PCV or EGR valve if its clogged, check if you fuel pressure is up to par. and check the air fiter.
Junior Member
Joined: Jan 2010
Posts: 76
Likes: 0
From: Crawfordville, Florida
Year: 1993
Model: Cherokee
Engine: 4.0
There is no MAS on our Jeeps. MAS stands for Mass Airflow Sensor, they measure the amount and temperature of the air going into the intake and are usually located down stream of the airfilter. Our Jeeps have MAP sensors, that stands for Manifold Absolute Pressure. It measures engine vacuum and sends the signal to the PCM to let it know how much load is being put on the engine.
CF Veteran
Joined: Feb 2010
Posts: 12,367
Likes: 23
From: Oroville, CA
Year: 1995
Model: Grand Cherokee
Engine: 4.0 with all of the noise and clatter
Now for the rough idle. The 5.2 has a plate on the bottom of the intake manifold, it sits down in the lifter valley. It is sealed with a paper gasket to keep oil out and the air in. If the engine has ever back fired through the intake chances are pretty good that the gasket might have been damaged and causing a vacuum leak, and may also be sucking oil into the intake. I've seen this happen a few time with the 5.2 and 5.9 Chrysler engines. So I would suggest that you fix the known external vacuum leaks, and if the problem is still there and everything else, such as plugs, wires, dist cap, rotor, injectors check out, then you should remove the intake to inspect that manifold plate gasket. Good luck.
Thread Starter
Junior Member
Joined: Feb 2011
Posts: 54
Likes: 0
From: arizona
Year: 1993
Model: Grand Cherokee
Engine: 5.2 318
So i tried to get my vaccum lines fixed but for the life of me cant figure out wut they are. Theyre a set of two mokded lines, that i havent checked where they go , but the plug into a connector that bolts on to the block close to the fuel rail. If n e one can help off the top of there head that wuld be awesome. Thanx
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