Engine Performance problem
2000 Jeep Cherokee 4 cyl Four Wheel Drive Automatic 135000 miles
Ok, so I bought this vehicle from a person who was told they had valve issues. Sure enough no compression, and one valve was stuck on the cylinder that was missing, cyl. #5. Had head checked and it was cracked between cyl. #3&4, common issue I guess. After alot of research, decided to buy an aftermarket cast head that is supposedly sturdier in the problem areas. Shipped from a machine shop in Florida. Put head on and still have same issues with bogging down, dying out, popping in intake on hard accel, valve clatter, only once nice and warmed up. Have compression back on all cylinders within spec. One rocker bridge was bent, off the same #5 cylinder, so replaced that. Replaced spark plugs, has coil on plug system. Reset all adaptives and afraid to drive to get fuel adapt relearn back, so not picking up misfires. Scoped crank and cam sensor today with Modis, nothing out of ordinary while acting up. Everything seems to be where it should on Datastream. Vacuum will start to flutter, 1-2 in, when acting up and once the valve clatter starts will actually drop 10 in or so sparatically, then back to same flutter spot. Checked at 3000rpm to see if drop below 10 in for clogged cat and it didint. Seeming to be a valve issue again but brand new head and compression is back, checked cold and after acting up. On first start up of the day vehicle will idle fine, none of the issues as before. Did not think to check vacuum while running fine. Maybe I should do that. Let run for awhile and the valves will start to tick slowly and if you give gas it will start the bog down on decel then starts with all the problems. Oil pressure will drop from about 50 on the dash gauge to around 20, still within spec on Alldata. Had it die a few times while driving at a stop and it will also do it occasionally while sitting at idle, usually pulls out of it before it bogs so far down to actually die. I work at a repair shop and eveybody is stumped. Saying take it to the dealer, but I would rather not have to go that route. Some have mentioned a lower end going out, but wouldnt the issues be there somewhat on the first start up of the day then just get worse, instead of just arrising after warmed up? Anybody who has any ideas or have dealt with same problem any help would be greatly appreciated. Thanks.
have the same problem?
Thursday, October 15th, 2009 AT 10:57 PM