check engine light on

a p0 300 is a random misfire code , not the egr , i would start simple , how long since a tune up ??? plugs cap rotor and wires

jim

Within 2000 miles I have done spark plugs,crank sensor,distributor sensor,fuel pump,coil pack,and main printed circuit board according to jeep factory mechanics.My last jeep recommendation was to do a valve job.I believe this would give a specific cylinder code and would not reset by turning the engine off and restarting. the condition happens at around 3000 rpm at highway speedsof 60 - 70 mph. I get a code p0300 and engine runs rough.I suspect emission controls

ok , have you checked the fuel pressure yet ???

spec is 44-54 while idling

there are many things that will cause this problem , if fuel pressure checks out , check compression

I ave checked fuel pressure at jeep I am told it was within specs. and if compression was bad wouldnt it give individual cylinder code?

not necessarily if two cylinders were low it would kick the 300 , there is so many test you could do ,im not sure if you have the tools or even want to check lmk

I have checked compression on all six cylinders within specs .when i get the fault and missing occurs I shut off the engine for ten seconds and restart the missing stops like it resets something electrical. thank you for the info!!!

may not be it but , ive seen the injector harnesses pull apart, do a wire shake test at the injectors , theone i found was at #2 on the injector plug, trying to help but not seeing it do it is tough , for this kind of problem anyway

Itried the wiggle test at 3000 rpm could not make unit fail.I have noticed that when the engine light starts flashing at highway speed if I accelerate the light will go out and usually comes on when decelerating thanks again.