SamCherokee

I have a 2001 Jeep Grande Cherokee 6 cyl inline 2wd 117,00 miles
Took it to my mechanic cause it suddenly started running rough
First he thought it was a bad injector. Changed it
Sitl running rough
Checked compression
3 and 4 had 60 psi
He thinks the intake valves have carbon deposits and need to be cleaned
Suggested I add intake valve cleaner to the tank and give it a good run. This might clean the valves
There is no water or oil leak.
There are no exaust fumes
The engine does not overheat.
I use the Jeep sparingly from my home to my job whech is about 10 minutes away.
Any suggestions?

Cummins93

https://www.cherokeeforum.com/f30/st...-4-0-a-226299/

I've not done it this way but I can attest to using water/methanol in forced induction setups that clean the engine well. I would not use any fuel additive or engine cleaners. They may work but appear to be unnecessary.

alpine.adrenaline

I'd start by using that free method mentioned above. It worked great for both my Cherokee and Comanche. Remove your intake hose, add water slowly and let the steam break up the carbon.

If that doesn't work to your satisfaction, do the same with some Seafoam, but once the engine starts to stutter as you're pouring it in, shut the engine off (have a friend at the ignition). Let it sit for 20 minutes or so, then start it back up. This will allow the seafoam to soak the carbon deposits.

The water method may produce a little cloud of steam and blue smoke from your tailpipe. This is the oil crud being burned off. Seafoam method will briefly blanket your neighborhood in a white fog as it breaks up more oil and burns off. There have been reports that this heavy white smoke isn't good for your O2 sensors, but I've never had an issue.

XJwonders

Yep. Do that thread first. Lol.

SamCherokee

Thanks for the input
Appreciate it!

00t444e

I use Marvel Mystery oil for that, it's cheaper than before and works as good or better.

fb97xj1

Which may result in your neighbors calling the fire department lol.

Oswalla

That 10 minute drive is actually pretty hard on the motor. Wife had an ol Fox Mustang hi pro motor with a 5 minute drive or less depending on how heavy her foot was. Had tons of carbon build up with that drive. After you do 1 of the methods above get that baby up to speed on the freeway, maybe rpm her out in 3rd for a bit. Got blow em out once in awhile with those constant short drives. When I decarbon, Ive done both methods, I prop the throttle open to 1500-2000 rpm while pouring in and take it the freeway afterwards. Pick a windy day if you use Seafoam, it will smoke the whole block up.