I recently purchased a '03 Chevy 3500 crew cab dually w/ approx 50K miles. The previous owner put a 6" tough country suspension lift and 315/75/16 tires. It is straight piped w/ no cats or mufflers. Unknown of any other mods.
I joined the site for some info and from what I have read I sorta think my truck "limps????" when I get into it hard. She will shift perfect every time during "normal" driving, but when I START OFF full throttle OR wanna "KICK IT" to pass she will get to around 55-65 MPH and bog out near RED LINE on me not shift into high gear. If I let out on it then drive normal it will shift fine to high gear the run on up to 80-90 MPH with ease! VERY BAFFLING TO ME!
Do I just need driving lessons or is something added to my truck to prevent it from being run hard like that? Any help from you guys is GREATLY appreciated!
Brad - bsw4newman12

 

If it was a "limp" you would have to pull over and re start your truck to get it to shift properly. But it sounds like a limp with the exception of being able to kick to 85-90 with ease.

Usually they limp with a programmer, the mods you listed I do not think will cause a tranny limp though.

 

if it goes into tranny limp it wont come out of fourth gear until you reset it by turning it off... something funky with your tranny maybe ????

 

I'm no help but......

 

change the fuel filter first.

does the check engine light come on? could be an engine limp or probably an engine overboost code. i see that it is an lb7 sometimes the truck will perform funny when its making too much boost and throw a code if its not taken care of with a programer

 

 

I'm with Danny on this one kinda what mine did when i forgot to change the fuel filter for way too long

and.....

 

Hey guys THNX for the warm welcome and answers. I do not get a engine light and i changed the FF like 1000 miles ago cause I ran her dry in the driveway and couldn't get her started. It looks like I should try that again... maybe my local coop is getting crappy fuel which is y it is only $1.99 gal right now! I sure am open to more advise but thanks for what I got so far!!!

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I put a BullyDog Triple Dog programmer on my truck and i got a P1093 and a P1621. Diagnose Check Engine Light Codes, Emissions And Oxygen Sensor Faults says the 1621 code is PCM memory performance....... They didn't list the 1061 so I searched google and got gm-diesel.com and some guy forum popped up and his truck does the exact same thing mine does. According to him "Auto Zone" says it is a fuel/air metering thing (X2) I am dumb enough that this still has me lost so if this helps some of u more mechanical guys to help me thanks again........

BTW......nobody responded to the other sites forum to answer that guys question..... sure am glad i found BOMBERS!!!!!!!!!!!

 

Sounds like low rail pressure. CP3 could be taking a dump.

 

Yeah. it's probably the fuel filter. I had the EXACT same thing happening to mine right around 45-55 mph. i got the fuel filter replaced and it ran perfectly fine.