engine help

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osmrc

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95 markviii when engine warms up to the r on narmal it kills the fuel to cylinders 2,3,5,8..got 2 exaust codes 336,337 and 1 trans code 624. anyone have a clue whitch could be causing this.changed both the sol in the EGR circuit,didn't help.
 
how do you know it is cutting fuel to those cylinders?
is the egr pipe broken? the factory flex pipe has a tendency to crack.
don't know about the trans code. probably a bad solenoid or bad wiring.
 
started out thinking It was an ignition problem.changed plugs,wires ther swaped coil pack from one side to the other,same problem.when it started missing we would pull the plug wires one at a time to see witch cylinders were missing.it was always the same ones only there was plenty of spark,so that means no fuel.changed the sol.in the EGR circuit,and the pcm,still the same problem.when the engine is cold it runs fine.when it gets to the R on normal it breaks down,it has a new exaust system and the EGR pipe is welded solid.
 
welded solid? is it still hooked up properly? if not, there's that code.

did you ever check your fuel pressure?
should be 42 psi engine off, 30 psi engine running.

pretty sure the computer doesn't shut off individual cylinders unless its dying or something. it doesn't have a fail safe mode or anything.
swapped pcm's you said? probably not that.

so fuel injectors themselves. but to have 4 go out? i don't think so.
wiring? but intermittent with temperature? unlikely.

so, whats left? something that changes when the car warms up.
the comp goes into closed loop. i wonder if you have a sensor going out.
o2s, tps, or something along those lines.

check for vacuum leaks as well. take a can of ether and carefully spray it around the intake. if the idle changes, you have a leak.
 
yep it is welded solid and hooked up with a little kink in it.Did the trick with the ether when I was checking the first time and have just changed the fuel pump.did not check the fuel press sense I changed the pump.maybe the reg. but the temp thing is what has us stumped.tps as in throttle position sensor could be but it went out a few years back and did not act like this.
 
Shot in the dark. Try replacing the cam position sensor. If not then you need to read the plugs. Dont just pull the coil wire and watch it spark, pull the plug and see if its burnt or saturated. Old dirty injector could not be atomizing when warm or stick open, both cases would show a wet plug. If the sensor is good and the plugs are burnt from no fuel as you suspect then the issue would have to be a broken harness.
 
well I did change the cam sensor did not help.printed off the electrical diagrams and went over them.I changed the PCM (got it at pull-a-part for $27.50) and after that I was showing a code for the EPC,which was not showing before.changed that same thing so when drained the trans again I put in a new TOT.while it was apart I started ohming out between the places that the enternal harness hooks to the EPC & TOT and found a problem.pulled the external harness off the transmission and found a short and the harness was starting to deteriorate so went to a salvage and found another one.It to was starting to show some cracking at the plugins (again at pull-a-part $11.50).cleaned it and put silicone around all the wiring at the plugs past where the cracks were.by the way couldn't get one from ford.put new loom material on and rewrapped with y88 elect tape.So far so good but haven't gotten it all that hot yet either.I looked at some others and they were pretty bad so this could be a problem you need to look into on any older markviii
 
wire harness for sure
the PCM deal could have been the harness and me moving it around produced the code.
 
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