87 YJ again....

Start with plugs, plug wires, cap and rotor. If this doesn't fix it then you are looking at the fuel pump or filter. This is a throttle body type of fuel injection, isn't it?

Earle

I thought the four-banger was injected. I could be wrong. My 87 YJ has a 258 (as did my 73 Cherokee and 78 CJ)

All the four banger AMC engines are fuel injected in the YJ. In 1991 they went from throttle body to MPI. The six bangers went from carburetor to MPI in 1990. I am not sure of the exact manufacturing dates. Service and replacement procedures are going to be different for the OP's throttle body FI than for the later model, more common MPI.

Earle

yes boys it is a Throttle Body....plugs, wires, cap, rotor, fuel filter all replaced a month ago

Watch the engine while it is running in the dark. I have caught spark leaks like this before. Another more painful method is to run your hands over the spark plug wires and distributor with it running. You could also check the plugs for evidence of fouling.

Earle

Right you are. My mistake. I conveniently overlooked the 4 banger part.

Scott

Many people do, but when you have them race balanced, install a wild cam, override the rev limiter, and install double injectors you can get a lot of power out of them. (I wish.)

Earle

EGR valve sticking open?

Spdloader

I would definately check/ replace your O2 sensor. This would give you the sporadic symptoms and in an 87 you probably have 150,000+ miles anyway...so its time to replace. Good Luck

Adam

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