So the other day driving to work the jeep randomly sputtered on me, gave it the gas to go an it almost back fired in a way/cut out like it wasn't getting fuel. Only did it for a split second and happened randomly 3 times. It would only do this when it was under load and on the highway. Got to work, put it I'm neutral and rev'd it up to about 5000 RPMS and not a single issue or anything. Anyone have any thoughts as to what this could possibly be? Maybe just some trash got in the injector maybe??

Fuel pump and filter, Plugs, wires, cap and rotor are all less than a year old and less than 10k miles.

94 XJ Sport 4x4 4.0

 

Well you did the pump/filter, cap/plugs/wires, so that's good....

CPS possibly? I thought that was usually more of a complete cut-out usually though, but it's a possibility.

 

What's CPS stand for? This is my first EFI vehicle so still learning names of parts.

 

Crank position sensor

 

I had a similar problem, replacing the TPS and CPS took care of it. I did them both shotgun style so I can't say which the problem was. I'd try the TPS first as it's cheap and easy and tends to develop bad spots at certain throttle positions.

 

If it's doing it under a load, it has the signs of an ignition problem to me, like a plug acting up with higher cylinder pressure, or maybe the distributor cap has a carbon track etc....
Of course the CPS has a lot to do with ignition also on these engines....

Just some ideas....

Hope you tell us what you find out.

 

Thanks for the heads up and the ideas. I think I'll go ahead and replace both the CPS & TPS as it's my daily driver with over 220k miles on it, doubt those have been replaced. I'll let ya all know what happens when I get around to swapping them out.

 

^^ Yes. Check over the plugs, wires and cap before you spend money on sensors.

 

 

Will do!

 

I just went through this with my jeep.... It was the cps. It will not throw check engine light but if u have access to a scan tool it will show up...

 

Can you take a look at my post : https://www.cherokeeforum.com/f2/hes...y-feet-202375/


And tell me if you had these symptoms? If so, I might try the CPS on my 98 XJ to fix my problem.

 

Checked your post........I'm thinking you have something else going on other than a bad cps....I'm not sure but it sounds like a spark issue. I'm sure u have checked but I would recheck all plugs and wires. I'm not sure of the symptoms of a bad tps......research the symptoms but I would rule out a bad cps.

 

My XJ doesn't have those idle issues at all. Will idle fine, rev up to 5k no problems. Just randomly and sporadically it will hesitate/stale/backfire almost in a way but had only done this when under load going down the highway and I step on it say pass someone.

 

Thanks for the heads up. I have a feeling it's the sensor as well as the plugs, wires, cap, pump, filter have all recently been replaced. Also it's always ran clean, plugs always look good when changing them. Think I'll go ahead and order the sensor as it's pretty cheap replacement part.