Engine Stalling or Losing Power while driving on 2001 Jeep Grand Cherokee

This problem happens intermittently, but is characterized by engine losing power, usually at speeds over 55mph and a couple times when accelerating quickly. I believe the engine may have stalled one day when I left the car started to warm up on a cold day. (I was positive I started the car, but when I went it out it was off) There is another thing that I think happened once, where it took turning it over twice to start, but I wasn't sure if it was a fluke. The engine stalling doesn't happen every time I've driven it, and so far it restarts in seconds or less than 5 minutes after quitting. The first couple times it happened, the car coasted and regained power on its own.
We've heard fuel pump/filter from several people, and ignition coil from a friend/mechanic.
any ideas?

Asked by for the 2001 Jeep Grand Cherokee
It really could be either so some testing is in order. Connect a fuel pressure gauge to the fuel rail and drive around (safely) keeping an eye on the fuel pressure when you lose power. If the fuel pump is getting weak, you will likely see a drop in fuel pressure when you get on the freeway because it can't feed the engine enough fuel.
Is your check engine warning light coming on? Fuel pumps don't always (almost never) set a light, whereas an ignition problem is more likely to set misfire codes
The check engine light does flash on briefly. Also turning the ignition on/off you can hear the wheeze of the fuel pump kick on.
After driving the car to O'Reilly's to see if the vehicle had thrown any codes, it refused to start in the parking lot. The guys at O'Reilly's seconded are friend/mechanic's hunch that it was sounded more like the coil being the problem and so I used a few of their tools and put in the coil in the parking lot.
Here I am back home and the car is running with a lot more power. I think we found the problem!
Awesome, glad you got it figured out. Fuel pumps very rarely set any trouble codes when they fail and ignition problems more commonly will turn on the light. The coil can be pretty expensive so I didn't want to say replace the coil if you weren't sure that's what it was. Were there any codes in memory? If there were, they should be cleared since you have fixed that. Unfortunately, that requires the scan tool
Well, I had took my chances being that I got to O'Reilly's and they didn't have a thing to test the codes. The jeep wouldn't start back up anyways and the guys at the store were so sure based on all the vehicle's symptoms that it was the ignition coil that I figured it'd be worth trying. I may've had to have the car towed otherwise since I didn't know if it was going to restart at all.
I may try autozone tomorrow and make sure the codes, if any are reset. Will disconnecting the battery reset the codes, or are they stored somewhere?
The book I have and this site says you need the scan tool to reset the codes. This site also says it will reset after 40 warm-up cycles if the failure does not repeat. 40 drive cycles could take a while but I don't know
http://www.wjjeeps.com/faultcodes.htm

Some cars after '96 can be reset by disconnecting the battery or removing a certain fuse but it doesn't look like that Jeep acts this way
Thanks for the helpful dialogue and suggestions.
7 answers 7 comments
could be the catalytic converter, this will also cause the ignition coil to fail
LMFAO...the misinformation you see on some of these sites at times is rediculous....a bad cat will have absolutely NO effect on an ignition coil.

If you have no clue what you are talking about you shouldn't even be posting.
I have been a certified mechanic in dealerships for 40 years and i had a Cat Converter make the coil fail. I took it off and beat the coil flat ----
I see a fuel pump relay http://www.autozone.com/N,14901258//shopping/partTypeResultSet.htm its either that or your fuel pump is intermittently going off then coming back on, you should be able to hear the pump when you turn the key on.
your issue sounds like it is fuel related, usually a coil or ignition componet is going to give you problems all the time. however with your check engine light on it could also be a faulty sensor. have the light checked first and go from there
sounds like your fuel pump is going bad.
Pcm Wiggle the wires on the pcm slowly and you can create the problem right then and there. i have had to replace mine 4 times already and now its ok. Check all grounds on the car and make sure you get that warrenty, mine did the same thing and i changed the pcm it was fine for 10,000 miles and all over again so i had taken it back to auto zone and it was free. Federal and califonia emmisions it dont matter it just makes a differance in the egr ciruit does not matter.
I have a problem with my 01 Jeep Grand Cherokee maybe you can help me with mine was stalling while driving and would restart immediately or on its own I replace the coil pack spark plugs and even put a new brain in it had no problems for the past seven thousand miles got back from a trip all of a sudden it stalling again I discovered a vacuum hose that had a crack so I did a repair on that it would go further than the time before before it would stall then I discovered turning the AC off and it would quit stalling turn the AC back on and it would run great with no more problems but after I park it for a while if I turn the AC on immediately you go down the street and it would stall again shut the AC off for a minute turn it back on no more problems would that be the throttle positioning sensor freaking out?