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joe moore
joe moore, ASE Certified Technician
Category: Jeep
Satisfied Customers: 639
Experience:  Technical school graduation ase certification in airconditioning
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1997 wrangler s: starts running rough and surges

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I have a 1997 Wrangler TJ 4.0, 5 speed, w/ac. After driving about 5 minutes it starts running rough and surges. Next time I drive it the same thing happens. I have replaced the fuel pump and module, oxygen sensor, plugs, plug wires, engine computer, and coil. No trouble codes. What do I need to do now?
is there a check engine light on? and if so, did you have it scanned?
Customer: replied 6 years ago.
There is not a check engine light on.
a simple throttle body cleaning and or replacement of the iac valve(idle air control valve) should clear you right up. you would be surprised at the drive ability problems this little valve causes, along with that , I would do what is called a top engine cleaning or "DeCarb". this is when you feed all cylinders with a cleaning agent such as SeaFoam, and it literally melts all carbon on the valves ,pistons ,egr tube and intake manifold,. and have your vehicle running brand new again. and one last thing, just for good measure, make sure the catalytic converter is breathing correctly. If you know that the converter has been replaced in the last two years, then disregard, other than that, you will need to have it checked.
joe moore and other Jeep Specialists are ready to help you
Customer: replied 5 years ago.
We replaced the iac valve and cleaned the throttle body and we thought it was fixed but the problem persists. Any other suggestions?
yes, you'll need to check the crank and cam sensors. crank sensor first. most times the crank sensor will not throw a trouble code, so it is overlooked many times
Customer: replied 5 years ago.
We replaced both but neither fixed it. What next?
ok check change the pcv valve , check the catylitic converter , question, when was the lat time the timing was set?
plugs and wires too. after these items, there is really nothing else it could be as far as the surging goes, oh, air filter and fuel filter/fuel pressure.
Customer: replied 5 years ago.
We will check these things and get back to you.