93 YJ stumble


knuckles06
04-27-2009, 01:12 AM
93 YJ, 4.0, 5 speed
The problems is it has a stumble problem. At low speeds it will start to jump like it lost fuel. I can make it do it also by hand by taking it to around 3000 rpm and back off slow. You can drive at speed with no problem I think I can still feel a stumble in it. But I had it on the interstate this weekend and run 90 mph no problem. I have changed the plugs and wires, disribitor and rotor, Fuel pump and fuel filter. I have check the coil and it's to specs. Fuel pressure is to specs. It did it before I changed the parts listed and it's still doing it.

fredjacksonsan
04-30-2009, 02:19 PM
Have you cleaned the intake/throttle body? Dirt in there can cause intermittent stumbling.

copperyj
05-27-2009, 03:13 PM
When the engine cuts out, does the tach needle drop real fast? That's what my YJ did. I ended up changing the Crankshaft Position Sensor. Napa had it for around $62. That took care of my issues.

knuckles06
06-02-2009, 05:36 AM
Cleaned injectors and air intake. Changed Crankshaft Position Sensor still no change....

fredjacksonsan
06-02-2009, 06:51 AM
Assuming you have replaced plugs/cap/rotor. Next thing I would suspect is the throttle position sensor.

knuckles06
06-08-2009, 12:34 AM
Changed the throttle position sensor that fixed the problem.

fredjacksonsan
06-08-2009, 07:19 AM
Sweet!

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