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Running rough

1106 Views 10 Replies 5 Participants Last post by  Mattstunt929
My 97 f350 has been running rough at idle and feelin a little weak at times. I took the truck to a local tech to put his snap on scanner on it. He tested it and said my number two injector was bad. So I ordered one and replaced it myself. The truck seemed to do a little better but felt like there was another injector acting up. So I took it back and re hooked up his scanner and it showed number two to be bad again?! So we scanned it again and it said there were issues with 6&8. So we scanned it again then it said 7 was acting up. So we ran it again to try and get a consistent reading and the last time it showed 6&8 again?!
Don't know where to go from here. Almost forgot on the third test the truck dropped a whole bank. I'm thinking valve cover gaskets and uvch.
Anyone else have something like this happen to them?
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did he buzz it? were the uvhc connectors tight?
Yea he buzzed it, that's when 6&8 would appear if I'm not mistaken.

On another note I've put a temp gun to the headders on a cold start and all the cylinders read pretty even except for the front two cylinders 1&2. They were about 20 degrees different.
The connectors look to be in place good
I am going to take a wild guess and say high mileage injectors. They may be working but working poorly. Probably shakes a bit on cold starts but after warm up gets a little better. You test the harness and see if its good, take the valve covers off and watch the injectors pump oil, but if they are original on a 97 with a couple hundred thousand miles on them, they have lived their life. Its a pretty basic system. If it has fuel pressure, power to the injectors (fuel and oil) and properly working poppets, it runs. Did he a run a CCT? Check the fuel pressure? Does it have good oil in it?
I believe they are original injectors. It actually seems to idle better cold. I've inspected the injectors on the drives side while running and they seems popping well (Oil spitting). Recent oil change with delo 400. Haven't tested the fuel pressure. What's the recommended pressure?
65 psi. If you can try a different idm and retest.
Now it's starting to feelin more electrical than mechanical. Feels like a bad miss now after it warms up. It's not all the time though.
Run some injector cleaner, might not help but worth a shot.
check your connections through the valve cover gasket. When I did injectors I replaced both just for good measure. also test resistance in the harnesses with an ohmmeter (inside from vcover gasket to ground/gplug/injector). I had similar issues, not running quite as bad as yours sounds to be. Replaced all 8 injectors, runs great (too good for the tranny). Much easier on the wallet if you can do them in your driveway too.
I checked the fuel pressure and it was 60 psi at idle. Gonna check hpop next just to rule them out before I bite the bullet.
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