94 4.0 dtc

[brios]

ok i have a 1994 4.0 splash 5speed 4x4 and yesterday going down the highway at 65-70mph it seemed like the engine just lost all power for a split sec. then it was fine then the CEL came on and the back off it done this 3 times before i got home then it went off and stayed off and today it done it once and now its staying on sry its so long but everytime i pull codes i get 12,76 and other idle codes but i pulled the bypass and checked it for movement when i turn the switch on and it did move so im looking to see if anyone else has had this problem

thanks

 

[Big Jim M]

If it felt like it was running out of gas...what about the fuel filter? That's when they usually show up, about 70 mph. Did it do that when you were driving slower and using less fuel? Start with a fuel filter.
Big JIm

 

[brios]

See that's what I thought too but I changed that yesterday and drove it to wrk after clearing codes lastnight and then today shure enuf at about the same place and same speed it done it again so I'm thinkin about putting a osiliscope on the fuel pump ? Maybe it has one bad winding that just shorts out at random ? Or am I over thinking this ? Thanks and good to know I want the only one thinkin fuel

 

[Big Jim M]

Tell us about that "place" where it cuts out. What speed. What rpm. How does it cut out? If you mash the pedal farther does it continue to cut out? Tomorrow drive that same place at fifteen miles slower..see if it cuts out then. I still think it is fuel related.
How low is the fuel in the tank?
Big JIm

 

[AllanD]

If you LIFT abrubtly does it run better, etc...

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[94rangersplash]

Check your relays make sure they are pushed in good and the doide thing make sure its geting good connection. Same thing happened to me in my 94 and the fuel pump relay wasn't plugged in good so if i hit a bump the right way it would cut out just like it sounds like yours is doing

 

[brios]

well it only seems to be doing it on the interstate at about 65-70mph in 5th gear ,around 2500rpm if i remember correct but i did do it early on the way back from the gym and i stopped for gas so now it has a full tank both from high traffic gas stations i frequent and i did fill up my work truck there so it cant be all British petrolems fault lol

could i have gotten a "bad" fuel filter?
also i used a ossiliscope to test the pump today and the wave fourm looked like it was out of a text book i also did a voltage drop do double check

and i checked Key on engine off the pressure at the rail and it looked fine

i checked the relays and all tested well with a ohm test

anyone think i should try another fuel filter ? or ?

and thanks for all the replys and help so far guys and a big to the inventor of alldata