||01-25-2010 01:26 AM
Engine knock and rough idle help
Hello everyone, ive been a lurker for awhile and have gotten some great advice reading the forum. I have a few noises comming from my tj that I can't figure out and was wondering if anyone could help me or has had similar problems.
First, I have noticed an engine knock that persists while idling until the engine warms up. It is not a clicking noise, but more of a solid 'knock' that is lower in pitch than the valves. It is slightly louder than the valves and when reving the engine it speeds up and becomes inaudible at around 2000rpm.
Second, I tried to fix this noise by replacing the spark plugs, but in the process created a new problem. Now my engine idles roughly until it is warmed up and the knock is still there. It shakes all over in the engine bay and intermittently bogs out a little bit. It's not that bad, but it did not do this at all before I changed the plugs. Also, a wierd thing, I don't think the plugs had ever been changed(has 97xxx miles on it), and the gap on the old plugs was like .09in. The plugs I put in I gapped to .035, would this have a significant effect on the engine?
Any advice on what to do next to try and diagnose these sounds would be greatly appreaciated!