1996 Jeep Laredo. 4.0 Straight six. Rear-wheel drive.
A few years ago my Jeep began running rough and the check engine light came on. A few days later the rough idle smoothed out and the check engine light went off. This became a reoccurring pattern, but with increased frequency and duration's of rough idle/ high gas consumption.
I bought a basic reader, but it only tells me multiple random misfires. Sometimes it is on cylinder 2 only or cylinder 1 and 5 only and other times (Now) it is on all 6 cylinders.
I tried fixing it by changing out plugs and wires, checking the gap on the plugs, cleaning the carburetor, and finally taking it in to my mechanic. He suggested changing out the fuel injectors, which didn’t help. No clogs in the rail either.
Recently my mechanic suggested it might be a bent exhaust valve and that it wasn’t worth fixing due to the potential high cost of needing to replace more than just the valve once he got into it. He said new found compression from fixing the problem might cause further problems.
Luckily it passed its smog test this year. Of course 3 days later it started running rough again, which triggered the check engine light.
The rough idle seems to be provoked by my lead foot. If I drive nice the problem occurs less often and for shorter periods of time. This last incident though has lasted over two weeks. The check engine light is still on but the idle has smoothed out a bit.
My questions are:
1. How could a bent exhaust valve cause the engine to run rough sometimes and normal others?
2. What is causing the rough idle?
3. How do I fix it?
I love the vehicle, but the frustration is getting to me. I’ll have to sell it soon if I can’t find and fix the problem!
have the same problem?
Monday, March 14th, 2016 AT 12:00 AM