I have a 91 XJ that I swapped a new 4.0 into. I used the long block, intake, throttle body, and accessories from an 02 TJ. All sensors and the ECM are from a 91. All of the sensors are new.
The engine starts fine, gets 17mpg, and runs fine, most of the time. I just drove it 2500 miles across country. When operating at speeds above idle it is smooth. At idle it stumbles (still maintains ~700rpm) all the time. Here is where it gets wierd. Occasionally it will run rough for several seconds and die. It starts back up and runs fine. I thought it was the CPS, but I replaced it with no effect. All the grounds have been cleaned and checked. After the trip I pulled the spark plugs and they are burning clear, so it does not appear to be running rich.
Anyone have any ideas?
TIA
The engine starts fine, gets 17mpg, and runs fine, most of the time. I just drove it 2500 miles across country. When operating at speeds above idle it is smooth. At idle it stumbles (still maintains ~700rpm) all the time. Here is where it gets wierd. Occasionally it will run rough for several seconds and die. It starts back up and runs fine. I thought it was the CPS, but I replaced it with no effect. All the grounds have been cleaned and checked. After the trip I pulled the spark plugs and they are burning clear, so it does not appear to be running rich.
Anyone have any ideas?
TIA
