I have a 2000 with the distributerless ignition system. When the motor is under load (ac on or defrost or nothing on or driving at a speed where i can hear the engine running) there is a ticking sound. It is not valvetrain noise it sounds like its an electric sound coming from under the hood. I had someone tell me at one time that it is a coil thats bad. Being the Jeep has the distributerless ignition, what would be the coil? Or whatelse could it be. No loss in performance whatsoever, just the annoying tick...

 

the noise most likely is a evap purge solonoid up on the firewall. the emission system runs test while the engine is running. hope this helps.

 

or a MAP sensor gone bad.

 

i have the same sound. mines a constant tick tick tick... when idling. i replaced the coil pack(coil pack is one rail holding the firing mechanism for the spark plugs, running along the engine at about 10 o'clock on the left side of the engine block) but to no avail. the only other cause would be sticky lifters.

my advice, replace the coil rail

 

i go with the guy up there that said it was the evap purge solonoid. My acts up once and a while and does that, it's on the passenger side about 8'' or so in on the firewall.

 

i'd try to locate it more under the hood. there's a recall on some of those, see if its by the cam sensor. makes a similar noise at the cam sensork, but it is the shaft turning the oil pump.

 

Its not intermittent. It does it all the time. I check out the coil pack. I do not think its valve train noise. I know that sound. But if it ain't really hurting nothing it will be like that for awhile.

 

Cam sensor it spins and it could be binding mine was like this and i let it go now the sensor and oil pump driveshaft needs to be replaced looking at 130 for parts