99 TJ Misfiring

[Jeff_R]

I have a situation with my 99 TJ that I am hoping someone can help me out with. My TJ misfires under low acceleration and at around 1700-2000 RPM. I have changed the plugs, wires, air filter, checked the PCV Valve, and the throttle body. It only does it sometimes. Hopefully some of you guys can help me out.

[tjdave]

did you do the fuel filter i've seen that before sputters at certain rpm..
also does it "miss" parked or just under load while driving

[Jeff_R]

It only misfires under load that i can feel. Is the fuel filter a difficult job?What type of filter is it and where is it located?

[tjdave]

yeah its a hard job its on the fuel pump in the tank you have to drop the tank and pop it out but if you unsure its best left to a tech.

get the fuel pressure checked it should be 14-15 psi at idle there is an adjustable pressure regulator if the pressure is high or low ther is ways of doing checks that will tell you if its a plugged filter or else..

[DYNNOMMYTE]

fuel pressure should be around the 40 psi mark... lat time i checked ...



-DYNNOMMYTE-

[tjdave]

my bad got my years mixed the tbi is is 14-15 psi
the mpi should be 31psi at idle with the vacuum hose to thr regulator connected 39psi dissconnnected..

[BadCompany]

im pretty sure there is no fuel pressure regulator on tj's. its a single line from pump to rail. i could be mistaken but the thing with the vaccume line on the rail is a fuel pressure dampner.