Guys, I am having a problem with my TJ I was hoping you might be able to help me with. I know this is long, but I wanted to provide all the info as I think the pattern has multiple factors.
2002 TJ 4.0L 5 spd 4.56 gears 63k original miles with 33’s
updated to remove commentary, I know this is long. so if you read the outline, you don't need to read what follows:
Symptoms
Thanks for hanging in there with this long post. Any help would be appreciated.
Jim
2002 TJ 4.0L 5 spd 4.56 gears 63k original miles with 33’s
updated to remove commentary, I know this is long. so if you read the outline, you don't need to read what follows:
Symptoms
- Stalling on the highway
- Sudden loss of power then stall. Highway only and only after driving for at least an hour
- Discovered that if I very lightly feather gas, it would limp along
- If I stopped and let it cool for about 30 mim I could carry on. Might or might not stall again
- Does seem to be correlated to the overheating problem below
- Decreased fuel economy and acceleration
- Normal fuel consumption was about 15.8-16.2 mpg (combined hwy / city)
- About this same time I had installed a Gobi rack and on the longer trips was using a cargo carrier. So was not sure how bad the fuel economy actually was. But then realized just city driving was really bad
- On this trip up north, with no cargo carrier, I was getting about 12-13mpg.
- Overheating
- Started to overheat when the AC on. Did not do this in the past
- Sudden “check gauges” light and in the red zone. AC off, windows down, heater on full, and back to normal operating temp in about 2 min.
- Outside temp was about 102 – 105 degrees, also up in elevation (5k-8k)
- When limping, O2 sensor voltage nearly zero
- Had the crank sensor replaced
- Performance drastically improved and was in elevations up to 8k feet
- After 100 miles fuel consumption was 16.1 mpg!
- Used AC without overheating but there were reduced air temps so overheating problem not confirmed as fixed
- Heading back home and it stalls again on hwy
- Had the AC on but noticed temp climbing (no check gauges light) so turned AC off but still stalled about 15 min later
- Just needed to let it idle on the shoulder for about 15 minutes
- Stalled again before getting home
- Once home, I filled up the tank to check fuel consumption – 11.4 MPG! Ugh
- Wondering if I had a faulty crank sensor sensor. Was not MOPAR which is my preference for such parts, but this was a NAPA part. I know if they are going to go bad, they usually do soon after installing
- Fuel pump only has 40 miles on it.
- Did not seem like the cam sensor, but wondering
- Bad ECU?
Thanks for hanging in there with this long post. Any help would be appreciated.
Jim
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