PCL

I have searched through countless posts and cant find my exact issue.
First I have an 03 Grand Cherokee Laredo with the inline 6 - 4ltr. Auto trans.
My tach issue is that it will go up to about 1900rpm and stick there. Also, if you hit passing gear it will go up to about 3100 rpm and stick there.
the glass is out of my inst. cluster and I can peck beside the tach needle and it usually goes back down to normal until you surpass 1900 or 3100 again.
This didnt really bother me much because nothing else seemed affected. Until today.
I was cruising up a long steep grade on an interstate with criis control on. When rpm dropped enough to make the trans downshift cruise kicked off and it lost power like I had pet off the gas. When I gave it more gas peddle it sputtered and jerked and would barely move.
I pulled off and stoped. Put in park and gas reved it up ok. Put in gear and would barely move. Noticed tach was stuck at 3100 again.
I cut off engine and tach dropped back to 0. Started it up and it drove fine.
Coming back on another long uphill grade I cut off cruise and tried that way. It did it again. Had to stop and shut off engine and it went fine again.
I did a google search and foundban article about holding in the trip ometer and turning key to on to reset the tach and speedo. I did that. Drove some more off interstate but tach kept sticking at 1900 and 3100 again, but it didnt stumble again.
I am thinking the tach messing up at higher speeds and rpms caused engine / trans to mess up. Maybe a limp mode or something.
Any odeas on what causes the tach to freeze in those rpms? And the stumbling engine?

charliec

I don't know about the tach but the stumbling sounds like a fuel filter to me.

PCL

Just put on a new filter and new fuel pump. 😕