Mechanics

97 4.0L NOT CALIFORNIA EMISIONS

1997 Jeep Grand Cherokee • 6 cylinder 4WD Automatic • 230,000 miles

Got a check eng. Lite. Got 4 codes o2 bank 1. High voltage bank 1. Same 2 codes for bank 2. The mil gave 5 results.02sen. /Compression/catalyst/ misfire/fuel and 1 incomplete.I changed both 02 sensors and cleared the codes. Drove about 20 miles/4 key cycles and codes came back. The truck ran like new after changing sensers and cleard codes but still had symtoms. When I first start driving cold or hot at about 20mph the truck chokes for 2 or 3 seconds, I pump the gas pedal and it usaly clears up till I shut down and resart. Also when I stop at a light sometimes the idle jumps between 200 to 600 rpm and the truck shakes, never stalls. Also noticed when im shifting from park to drive/drive to reverse the rpms will drop and the truck will rumble. This corects itself quickly, 1 or 2 seconds. Ive done some work, these problems existed prior to the work. Plugs, cap rotor. Had a clogged catalitic converter. Changed it. Cooling system was very muddy to the point where I had no heat. Flushed the coolingsystem several times. Air filter. Got a small crack in exaust manifold. Fuel filter is in the tank, truck has 230,000 miles on it. Ive had fuel filter problems with other vehicles and the symptoms were very different. Oh the temp gauge on the dash is working fine but I was told it may have 2 temp sensors. 1 for dash and 1 for computer. Im hoping you can steer me in the right direction. I can just keep changing sensors till I get it but shotgun diagnotics are expensive. Thanks for the help
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Dennis5325
February 24, 2011.



When have you cleaned out you throttle body last?
Possible throttle body carbon build up. Does the gas pedal kinda stick at all?

Tiny
Jcninja636
Feb 24, 2011.
Hello,

Ok, check for vacuum leaks. Remove and clean the IAC (Idle Air Control)Valve. Also the Crack in the Exhaust Manifold can be causing false readings on the O2 Sensors.

Obxautomedic
May 8, 2011.