rough idle 91 explorer

[newfie-explorer]

new to site been reading the threads for a while now, i have a 91 explorer, rough idle, no hesitation, new plugs, wires, fuel filter, injector cleaner ran through many times, i run it only on supreme gas, no CEL codes, the only thing i don't know is if the fuel pressure regulator is causing the problem, when i bought the ex, it wasn't running, i got a pressure reg. off a 93, had to change the fitting from the plastic, snap on one to the screw on one, was wondering if the pressure regulator on the 93 had different pressure rating than the 91, i can't seem to find any info on this

 

[MrShorty]

Nope. '91 to '96 or so 4.0's were all spec'ed at 40 psi. If I suspected a problem with the fuel system, the first thing I'd do would be to put a fuel pressure gauge on it.

 

[marragtop]

Check all the vacuum lines on the vacuum tree located drivers side by the firewall.

 

[newfie-explorer]

thanks guys, will be sure to check that, when i get it back, lost the tranny, for the 3rd time in 5 months, first one blew out front seal and fried, 141xxx kilometers, bought used one with 185xxx burned up on the highway after about 1500km, no fluid loss, didn't get hot:scratch: weird, had it rebuilt, installed it, had no reverse, and wouldn't shift when it was cold, returned to tranny shop, waiting on verdict. :scratch: