[gunny]

'03 with 175,000 miles. Stock exhaust and Super Chips. Super Chips in the tow safe mode. Allison automatic. Surges when cold, for the old time Detroit mechanics, soulds just exactly like an old 8 V 71 when its cold. RPM surge up to 1200 and then immediately drop to idle, 3 seconds later, does it again. Doesn't do it when hot/warm. Been getting worse lately. Stock fuel filter (new filter) with a Racor ahead of it.

Thoughts? Ideas? Comments?

 

[duramaxsandwich]

does it still do it w/ your ecm programmed back to stock?

 

[05_LLY]

sounds like it posibally could be a bad fuel pressure regulator , i have never experienced one bad but the symptoms sound right!

 

[proboat-wes]

never have heard where the fuel pressure regulator is located on the engine .any help or pictures out there?

 

[dsaalfrank]

Mine was on the top of the engine, in the front. Just below the thermostat housing.
Three Torx head screws. The first one was out in 10 minutes. The second one was out in 30 minutes. The last one took about 2 hours, I had to come up with a combination of tools to get down into it.
Have fun the dealer wanted 5.5 hours to do the job. I did mine in about 4, even replaced both thermostats.
Doug