1997 Jeep Wrangler Poor gas milage, rough idle, check engin

OLRNDRT

MEMBER
1997 JEEP WRANGLER

Engine Performance problem
1997 Jeep Wrangler 6 cyl Four Wheel Drive Manual

Had been operating normally. While on the interstate, check engine light came on. Except for rough idle, every thing seemed normal. After approx. 100 miles, noticed fuel consumption was very high. At end of 400 mile trip consumption had more than doubled. Clerk at Auto Zone read computer codes. Said there was a vacuum leak. I checked all lines and manifold gasket with aerosol solvent. Found no leaks but did find crank case vent open in both directions. Repair manual states that, on this mod, the PCV was replaced by A CCV which has the same function and is tested in the same way. Auto Zone and NAPA can not find this change in their computer and found no PCV for this engine. The unit which I believe to be defective looks exactly like the photo in the manual. I have eliminated this part by capping the vacuum line at the manifold. Check engine light is still on.

Could this part cause the symptoms described?
Does the computer need to be reset to turn off the light when the problem is repaired?
If this is not the actual problem then what should I check?

3 Replies

AIRSOFTSOLDRECN9

MEMBER
348 POSTS

Since the advent of the wranger pcv systems are not a part of the emission system. CCV or Crankcase ventilation is continuously running and will pull vacuum all the time from the valve cover. Make sure the gasket on your valve cover is ok. Get a vacuum guage connect it to that line you disconnected and see what happens. It should be hovering steadily around 17-20 inch. Vac. At idle. Make sure your EGR works correctly otherwise that will cause all kinds of problems. Let me know if you get any other readings or what kind of readings you get. (I.E. Moving up and down, erratic, and under what conditions)