99' F350 Coughing/Sneezing

[Joe83]

I recently purchased this truck and it has a few issues, one being..
When I am merging on to the interstate, if I really put my foot into it, when the RPM's get high it will "****" and buck....
Then will carry on as nothing happened.
If I am cruising, then hammer down, when it down shifts it will do it then as well...

It only happens when I really get on the pedal hard, just normal driving it purrs like a kitten.

Also, another symptom, while idling, it will idle up and down 50-75 maybe 100 rpm's.
Just enough you can feel it and see it in the gauge.

Any help would be appreciated!
Thanks, Joe


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[79jasper]

Have you changed the fuel filter?

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[Joe83]

Man, I just bought this thing...
"Supposedly" it just had all of that changed...
I know the oil is fresh, still clear.
I would assume the fuel filter was changed also.


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[79jasper]

I would check it anyways.
A little bit of engine shake is normal for these.

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[Joe83]

Engine shake being the idling up and down or the "****" ?


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[IDIoit]

I know the oil is fresh, still clear.
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that would be a first! lol
everytime ive done a oil change the oil instantly gets dark.
even after i resealed the oil cooler

the best thing IMO is get it on a scanner and check the readings in real time when it happens.

 

[OLDBULL8]

Lots of things will very the RPM at idle, such having the AC ON, weak batteries, PCM will cause RPM speed up to charge at 13.7 VDC., IPC and IPS, nothing to worry about.
Never assume anything on a used truck, check the fuel filter, clean out any gunk in the bottom, don't remove the center post, if you do it's a left hand thread.
Lack of fuel PSI at WOT until fuel supply catches up to RPM. You could install a fuel guage, dieselorings has all the fittings necessary, fuel pressure has to be maintained at 45 PSI, fuel pressure is normally 65 PSI.

If the IPC (Injector Pressure Control) has oil coming out the wires, it needs to be replaced.

Sneezing & Coughing, Need address to send a large box of Kleenex.

But , could be over boost, if turbo wastegate is not opening all the way or mis-adjusted. Disconnect the RED tubing to Turbo and plug it, see what difference that makes.

Throttle Pos. Sensor (TPS) can be loose or out of adjustment or dead spot at WOT

Buy an AutoEnginuity scanner to monitor paramiters, that'll tell you whats wrong if anything. Good tool for any PSD owner, saves going to a Dealer, Dealer charge is $100 and up for a scan.

Edit: A crossover tube between HP oil rails is a good thing, balances the oil PSI between rails.

Edit 2: Put your trucks info in your signature. And how many miles on it.

 

[Joe83]

Thank you.
Until I add info...

Early 1999 Ford F-350
Crew Cab, Long Bed, Non Dually
244,000 miles


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