I purchased a 2004 grand Cherokee laredo special ed with 85,000 miles on it in August. Since then it has been towed 4 times and I have had it for about 1 week total.

At first it would almost die when I went from the break to the gas at red lights. After stopping at a store it would not restart. It would turn over, all systems go, but would not start. The mechanic said it needed new plus and fuel filter. After replacing those it started and ran for about a day before doing the same thing. He them said it had to be the pump. $500 and a new pump later it ran for 3 days before dying while I was driving. If left a few hours it will start again and run for about 20 minutes before dying again.

Any ideas? He is saying it may need a new ecm but I highly doubt that.

Please help! $1,000 gone and still no progress!

 

It could be the ECM but it could be a few other things too like the CPS, ASD relay, Fuel Pump relay, or a loose connection somewhere. Don't really have enough details to make a diagnosis.
You can try tapping on the ECM and pushing on the face of it and even wiggling the connectors on it while it's running to see if it causes the engine to stumble or stall or alternatively give it a light smack if the engine won't start to see if it fires up. Most ECM issues are cold solder joints or weak connections.
Also inspect the wiring from the O2 sensors and CPS to see if they've been chafed or melted by the exhaust and are intermittently shorting to ground. Wouldn't hurt to inspect other sections of the harness for chafing/melting.

 

mine kinda had the same problem it would run fine then just die while driving down the road and if i let it idle for like 10mins it would shut right down. Mine ended up being the crankshaft sensor but mines also a 1996 so yours has more in it then mine does but that was what my problem was.

 

With the newer Jeeps, if you have that problem it could be a vaccum leak as well. First and foremost, check your battery terminals. Any corrosion build up will cause it too not start at all. You might have to replace the terminals too. Usually you can find a good set of terminals at Autozone for a few dollars. But as the first poster said, missing alot of details.

 

Battery is new and terminals are clean. Mechanic said the fuel pressure drops to 10 psi randomly. I am calling him today for an update and I will post his answers. what questions would you like the answer to?