97 f250 hd, extended cab, 2wd short bed. purchased in feb. 08. ive replaced fuel injector o-rings, fuel pump, ipr valve, cleaned the screen inside the fpr, trans rebuilt w/ shift kit and billet triple disc converter. ive ran sea foam, trans fluid, 2 cycle engine oil, stanadyne, diesel kleen, you name it, ive tried it. ive replaced the fuel filter at every oil change, oil changed every 5k with rotella and a quart of polydyn tx7 engine treatment and the oil is still light brown every oil change with 341k on the clock. i have a k&n filter, 3 in. downpipe, free flow 4in. exhaust with an 8in. tip, edge evolution tuner, running in extreme mode most of the time, although its been run in all 3 modes and it still responds the same way with the tuner or without. i used to run a superchips max micro tuner and it did the same thing then as well.

what it does:

from time to time the rpm's fluctuate between 630 and 740 rpms erraticly. doesnt do it often but it does happen. real sluggish going up hill at around 55-65 mph. very rough idle between 1500 and 2000 rpms.

im at wits end here.

i was told to do exhaust, make it free flow. so i did. no change.
i was told to do an intake, make it breathe better. so i did. no change.
i was told to check the wiring harnesses at the valve covers, make sure nothing is broken, burnt, or damaged. so i did. no change.
i was told theres water in the fuel, drain the bowl. so i did. no change.
i was told bad injector o-rings, replace them. so i did. no change.
i was told all these different additives, use them. so i did. no change.
i was told it was torque converter slipping, rebuild the tranny. so i did. no change.
i was told the ipr valve was bad or clogged, replace it. so i did. no change.
i was told the screen inside the fpr was dirty, clean it. so i did. no change.
i was told to unplug the icp, see if it changes. so i did. no change.

****PLEASE HELP ME HERE, SOMEBODY!!!****

 

Have u plugged it in to a scan tool yet? But u might look at the throttle positioning sensor that's kinda what it sounds like

 

injectors stock? thats a lot of miles on them. take it to a good shop and they can run some test on it. just had this done on our 95 with 235k on stock injectors and they told us injectors. replacing in 2 weeks.

 

cct came back good. ibt came back good. tps tested fine. anybody heard of a trs - transmission range sensor? which, in my mind even if it was this trs, that would only explain the sluggish feeling at high speeds on hills. what advantages are there to the 6637 upgrade? ive been running this k&n since i bought the truck in '08. it was one of my first mods. i keep clean and oiled with the cleaning kits k&n sells at least once every 2 months if not once a month. just wondering if theres any noticeable power, performance, or sound changes by switching over to the 6637. any input would be appreciated.

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also curious about the fpr shim mod. hows it done? what alls needed to do it? can it even be done on a 97?

 

Need to get a scanner and do a buzz test and cylinder contribution test.

You have a super high mileage motor and 10 years of previous ownership that you can't account for...

An FPR shim is just a bb in the fuel pressure regulator. It's not going to help your issue and only needs to be done if you are having low fuel pressure.

There will be no noticeable difference with a different intake unless your intake is completely clogged...

 

cct = Cylinder Contribution Test - came back good

ibt = Injector Buzz Test - came back good

intake isnt clogged at all, just keep seeing that 6637 mod and wondered about it.

and the FPR shim i had heard about before and was wondering about it.

im gonna do a fuel pressure test this weekend, what does it need to be at?

 

60 +/- 10psi at idle would be fine...

 

just did the FPR shim with the BB. throttle seems more responsive but truck still stumbles same as before. fuel pressure was 50 before BB, 70 after BB. unfortunately i dont have money to do an e fuel conversion. im curious about the 14.7k resistor mod. i keep seeing that everyone whos doing the resistor mods are saying they dont have chips or programmers on the truck. is doing the resistor mod in line with the blue/red wire on the ICP not recommended with me already having the edge evo on the truck? some help would be appreciated if anyone knows anything.

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Just got back to the house. When I left the house I unplugged the map sensor. Leaving here the truck seemed fine. First uphill attempt it seemed to not be sluggish. I thought, you gotta be kidding me, all this time it was the map sensor, nope. My EOT was at about 96° then, as it warmed up to around 138° and I attempted the next uphill journey the stumbling was still very noticeable. So I went and plugged the map sensor back up and unplugged the ICP sensor. Of course the engine did the little skip that it does when it switches to the factory ICP setting and the truck seemed to rack a little when idling. I pulled off and started my first uphill attempt. Seemed to not be as sluggish and then on the next one it still showed its sluggishly ugly head, engine oil temp now is around 146° or so. I come to a stop and when I go to pull off the truck starts slamming into the gears, almost hard enough to bark the 285/75's on the truck. I do have a billet triple disc converter, all billet internals, larger valve body, and a shift kit in the trans. So I pulled back over, plugged the ICP back up, cleared the codes both sensors put on the screen, the racking idle smoothed back out and the hard shifting stopped and I brought her on home with no issues, minus the sluggishness.

So that rules out the map sensor and the ICP sensor being bad, right????

Any thoughts fellow Diesel Bombers????

Anybody ever heard of a Transmission Range Sensor (TRS) or know of it ever being a culprit in scenarios like mine????