okay so my truck is a 97 12v and has stock lift pump on it how much HP can a stock one withstand? and it spits and sputters when reving? it also has marine 370's in her whats you guys thoughts

 

I asked a shop where i took my truck to when my stock lift pump was going out the same question.And they said the lift pumps on the 12v's can handle quite a bit of hp.

 

IMO around 400hp is the max for the stock LP.....they can do more but it's asking a lot. Put a fuel pressure gauge on it anc check out the pressure. Lines that suck air can cause issues and they won't always drip fuel. Also check the OFV but you'll need th epressure gauge for that too.

 

500 is max but i wouldnt push it that high becuase you are start starving the ip not a good idea if you want to go higher get an airdog or fass unit its a piece of mind thing

 

And once you get above 400-450 hp a 12V truck needs a 200gph electric pump......

 

okay thamks guys i think i got some wierd problem she is missing when you get on it hard or rev fast. already changed fuel filter whats your thoughts, timing?, LP?

 

 

how is oil pressure?
has it ever been in the hot zone.
did you mess with timing (wondering why you would bring up timing)
do a compression check

this is where I would start.

 

Other than whats been mentioned in reference to lift pump.....(check pressure etc)
I'd say your timing slipped.
Mine did this with DDP2's and slipped timing (12*)
It popped and cracked worse when revved without a load.

BTI

 

it runs decent with a load almost as if it advanced itself. i just got this truck just diagnosing it