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89 4.0 jeep cherokee runs rough help!!!


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Carlbob
02-06-2008, 02:23 PM
I was driving the other day and ran low on gas and it started to run rough so i got gas and it still ran rough like it didnt want to go so i thought i needed oil so i checked it and it was fine so then i drove it home and everytime i steped on the gas it would hesatate so the highest i could go is 35 mph then i gave it a tune up when i got home and changed the fuel filter and fuel pump screen and now it runs but its really rough and still hesatates anything yall can think of i would apprecate it.

AlohaBra
02-06-2008, 03:02 PM
I would check the distributor cap and rotor. Then the spark plug condition. Do you know when the last time these things were serviced and inspected?

Other things could be wrong, but you need to confirm the basics.

Carlbob
02-06-2008, 04:27 PM
ya i allready changed them all its seems like its not getting enough gas to the engine

AlohaBra
02-06-2008, 06:59 PM
OK...assuming you measured your fuel pressure and checked a fuel sample for contamination.....I would test the TPS..throttle position sensor.

Carlbob
02-06-2008, 08:24 PM
ya i changed the screen it was a lil clogged but then i ran it then was told that i should change the fuel filter so i did and i dumbt it out and it was brown so i knew the filter was clogged so then i blew out the line and now the jeep runs but its running rough so i think it has something to do with my cat converter like not enogh air is coming out

gtmud
02-06-2008, 11:35 PM
find out your fuel pressure, you ma have a weak pump.

dave92cherokee
02-07-2008, 06:30 AM
Sounds like you should check your TPS as alohabra suggested and also check your map sensor. I know from personal experience if either of them is bad or the vacuum line running to the map sensor is bad could cause it to run rough and hesitate.

fredjacksonsan
02-07-2008, 11:19 AM
I'd start simple and get a good fuel additive that'll take the water out....since you've covered most of everything else.

Carlbob
02-07-2008, 04:37 PM
i think the timing is off so im gonna get that done then if it still does it then ill check the tps

wwwildman
02-07-2008, 07:47 PM
i think the timing is off so im gonna get that done then if it still does it then ill check the tps

Timing is controlled by the computer and is not adjustable.
Check your fuel pressure and then TPS and MAP sensor as suggested above.

dave92cherokee
02-07-2008, 11:28 PM
You also might want to go pick up a mechanics stethoscope and check for any vacuum leaks.

Carlbob
02-08-2008, 03:48 PM
why would it be backfireing into the carb?

AlohaBra
02-09-2008, 09:37 AM
Although the timing cannot be adjusted, it can be checked with a timing light.
There are timing marks, but they are hidden by the serpentine belt pulley.

Two things are possible also:

timing chain worn (along with gears)
spark plug wiring crossed or miswiredOtherwise:

TPS
Map sensor
CPS
plugged CAT

Carlbob
02-09-2008, 09:03 PM
ok i changed the map sensor and still nothin so i had a guy comelook at it today and he said my ignition coil is bad so its not kicking over

Carlbob
02-10-2008, 12:32 PM
ok i got it running and its still runnin a lil rough so it wasnt the ignitin coil but its sounds like its not hitting all cylinders so i was thinking its the wires the one things i havent changed yet?

AlohaBra
02-11-2008, 07:10 PM
Easy check...pull each wire with an insulated plier/tool made for that purpose.
Each cylinder with a good wire will drop in rpm. The cylinder that does not show a difference has a problem....with ignition or compression...etc.

Carlbob
02-11-2008, 09:17 PM
ok so i get thecar running then pull each pulg and see which one doesnt drop in rpm's and then what do i do to fix it

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