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New F250 Owner
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Discussion Starter #1
Hi. I notice an oscillation or very mild stepwise surge in RPMs, and am trying to find out why and if I should be concerned. I have searched about "surging" but I don't think this describes my problem.

I have a 2006 F250 Superduty 6.0 Powerstroke. It has 94,000 miles with a 52,000 mile engine (due to injector failure). Since I've recently acquired it, I've put in a new EGR valve, fuel filters, new head gasket, aftermarket studs, and a high-pressure oil pump. I use it around town, hauling a few crabpots, towing small boat, and to occasionally pull a 13,000 lb. fifth wheel.

I notice an irregular pattern in the RPMs that makes me not trust the truck. While accelerating/climbing the RPMs go up in a stepwise fashion. It is not when shifting gears, which seems smooth, but during the ramp up of RPMs within each gear. It goes up 2-300 RPMs, then jumps up another 200, etc. You can feel the truck pull forward in this stepwise fashion. While driving in a constant RPM situation I will also notice the RPMs oscillate about 20-40 RPMs (mild, but noticeable). It does not significantly surge; the problem is pretty mild. It's barely noticeable in low demand situations, but if you really accelerate from a stop or are going uphill, the stepwise progression is much more noticable. There does not seem to be any loss of power. It does it most of the time, although sometimes it seems to ramp up RPMs normally/smoothly. It's more noticeable while cold, when towing, during acceleration, and climbing.

To sum up, the RPMs oscillate mildly while driving down a level road and usually the RPMs ramp up in a stepwise fashion 2-300 RPMs a jump while accelerating. It's more noticeable when the engine is cold and while towing or really accelerating.

Should I worry about it? What should I have looked into or replaced? I took it to the dealer describing the problem and got a new head gasket - it still does the same exact thing with the RPMs.
 

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New F250 Owner
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7 Posts
Discussion Starter #3
Thanks for the comment. I will drive it like a bat-out-of-hell weekly if that will clean things out.

However, I have a new EGR and when the rebuilt engine was put in in February (only 3,000 niles ago), the turbo was cleaned. So, I don't think that is the problem.

I've been adding a cetane boost product but just started doing that. Hopefully that makes a difference.

Anyone else ever notice this jumpy RPM ramp up? I'd really like to know what the deal is because I'm reluctant to rely on the truck on vacation or towing stuff.
 

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New F250 Owner
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Discussion Starter #4
Has anyone else noticed this symptom? Any input would be grand.

Does anyone agree with 2 stroker that it's probably just carbon deposits in EGR and turbo?

Does driving fast really clean this stuff out?
 

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mine did something like this but it wasnt as noticable in the higher rpms. and before it was warmed up it would dang near throw you out of the seat. but mine ended up being the exhaust backpressure sensor.

and you have to get it hot every once in awhile to keep the turbo and stuff cleaned out
 

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New F250 Owner
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7 Posts
Discussion Starter #7
Don't know fuel pressure but wouldn't there be other symptoms if there were a problem with that? The problem is subtle and sometimes she runs fine.

The big issue is it was worse when I was towing my fifth wheel and now I'm nervous about towing it again. I don't want to get stranded with family in the truck and no shoulder to pull over onto.

No codes or engine warnings. It threw an EGR code until I had a new one put in.

Sounds like people feel you should drive around fast and/or get the engine temp up to clean stuff out?
 

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its not the engine temp you want up its the exhaust temp you want up, but in turn to do that you have to drive it like you stole it or put a heavy load behind it.
 
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