I’m having an intermittent miss or surge… I’m really not sure how to describe it… so bare with me please.

at any point in time, taking off with a slow ease into the throttle, or getting in it pretty good. To crusing on the hwy 65-70mph. The truck can be warmed up running on the interstate all day, or 5 min after starting it in the morning… sometimes when I take off… it’s feels like you’re mashing the pedal to the floor, then letting out real fast, then mashing it again, then letting out… kinda like driving a car with a super sensitive pedal on a REALLY bumpy road. Like it’s trying to go, then falls flat. When idling it feels like a miss. It’s very random.

in the last year I have completely been through the entire wiring harness, cleaned and reseal the fuel bowl new poppet and all, I did install the “medium” fpr spring, changed the uvch, just changed the air (Napa gold 6637) and (Napa gold) fuel filter, rotella t6 every 3-5k, no oil in the ipr or ipc.

As of 2 weeks ago the truck is tuned, stock haydra tunes, bought the hydra from jellybuilt. jp3 port was cleaned properly. These symptoms aren’t new, they existed before the hydra. But the hydra did seem to amplify the issue. I typically run 40-65 daily driver tunes. Haven’t towed with it yet.

im running the edge cts3 for gages.

when it’s warm and idling it reads 470-490 icp at 10% ipr. I’ve noticed when the “miss” occurs, the icp will very quickly drop to around 350ish-430ish for just a split second then it’s back up. It will go back and forth like that for a few min, then it clean up and maybe won’t miss for the rest of the day, OR like today, it will be doing it off and on all day. I’m just at a loss.

the truck is a 01 ccsb 4x4 auto trans. 296k on the clock.

any ideas?

 

Could be time for new injectors.

 

That’s what my gut is saying too… but my wallet is in denial still. Are there any other possibilities? I haven’t dropped the tank and checked the pickup screens or done the hutch mod… Is that even a possibility of being the issue, realistically? CPS maybe…? Maybe switching back to the stock fpr spring? I’ve had the truck for about 2 years. I run diesel kleen pretty religiously, it honestly don’t seem to help or hurt. But this is starting to become a pretty persistent issue, and now that I’m tuned, it’s sucking all the pleasure out of finally having a truck that will get out of its own way. Along with not knowing what else I’m screwing up while driving it wounded.

 

Throttle position sensor getting dirty?

 

IDM could need rebuilt also.

 

how do I rule out one or the other?

 

That’s def something to look into that I didn’t think about.

 

Send the IDM for testing and likely rebuild. Injectors are past their lifecycle, so I'd recommend replacing them. It's not worth testing at that mileage.

 

recommendations on who I should have test/rebuild the idm, and injector size?

end goal is a mild build, 38r/kc300, up pipes, evbp delete (I live in FL no need for it), s&b intake, already have 4” turbo back exhaust. I’m a PMR truck so I’m after a reliable 400 horse work/pull truck. Will something like a 180/30 injector support that well? Or stick with stock injectors?

 

May be worth noting that the truck sees weights anywhere from 14k with empty trailer, all the way to 25k on occasion. I’d say 30-40% of the time I have a trailer behind me.

 

Injector size choosing is best based off how you plan to use the truck, and if you are willing to buy supporting mods for larger injectors to make the power desired.

Def go with a kc300x turbo vs a garrett 38r

 

what’s a good injector I can install now but support a turbo later? Is there such a thing? The truck does a little bit of everything. City driving (Tampa bay/st.Petersburg area), interstate, and we pull dump trailers and light equipment. Average weight is between 13-18k. Truck has seen 25k on occasion. I’d say 30-40% of the time I have a trailer behind me.

 

I'd say 160/30s and a good tow tune would work well. The next size up would be 205/30s. I don't recommend 180cc injectors to anyone.

 

Sounds like IPR sticking/loose wire or pedal switch acting up but that drop of ICP to that low would have me looking at IPR and not the switch

 

Thats a good bit of weight, a fresh set if stock, 160/0 or 160/30 would all work for you.
The single shots will require custom tuning, but provide more power and less demand on the hpop
More power will add more strain on your transmission.

Have you checked for blow by?
I would also suggest checking post filter fuel pressure first as well