hey guys,

So when I first bought my 96 Cherokee (4.0 I6, Auto) it was reading all 6 cyl misfire (P300-P306). I replaced the plugs and wires and cleared it. Filled her up with gas to see if it would go away, and sure enough it did. Drove her home from school for the weekend and the check engine light came on once it got to a 1/4 of a tank. Showing a misfire in Cyl1. Then I filled it up on Saturday night and this morning it wasn't showing a misfire.

I am confused on why it is showing a misfire once below a 1/4 tank of gas.

Thanks

 

have you done it a second time at 1/4 and had the same results?

 

The 1/4 tank thing might be a coincidence. As mentioned, see if you can repeat it.

You replaced the plugs and wires. The distributor cap and the fuel injectors are still in play as suspects for misfires.

Pop a new cap on there for starters; it should be part of every tuneup and a new one will be under $20....I like the NAPA premium caps with brass contacts.

Another possibility for random misfires (P0300) and other misfires can be marginal fuel pressure. I would verify the proper spec for fuel pressure on your 96 and verify it with a fuel pressure gauge which can be rented from many parts stores. 96 was the year of change for the fuel system. Early 1996 models require 31 psi at idle, later models require 49 psi at idle. Be sure you know which fuel system you have. If you have a fuel filter under the driver's side door, you have the early system, from what I remember. Others please correct me if I'm wrong.

Good luck and keep us updated!

 

were you able to repeat the problem?