I have had this annoying problem for about a year now. When ever the fuel level gets below 1/4 tank the truck starts having some idle issues... It will surge and sometimes die... But it only does it when it is below a 1/4 tank... I am starting to think it is my fuel pump. Another reason i think my fuel pump may be weak, is my VE values in the 95-100kpa range are above 110%, i think i peaks at 115%... I have 31# 8.1L injectors and my IDC is about 74%.... I have put a mechanical fuel pressure gauge on it before, the fuel pressure was good, except i had about 4-5 PSI drop at WOT...

I only have issues at idle when it is below 1/4 tank, once off idle it is the exact same.... My LTFTs stay about the same the no matter what fuel level i am at... The only other thing i can think of is there might be some emmissions test that occurs below 1/4 tank...

Any ideas?

 

disable all emissions related codes and see if that solves your problem, what is your fuel pressure when the problems occur?

 

shouldn't fuel pressure go up when the throttle opens?

 

I got a new fuel pump on the way. So hopefully that should ruleout the pump and make my ve table a little more realistic

 

You going to drop the tank or lift the bed? I'll give you a hand either way.

 

Actually i have read about people just sliding it backwards some... Sure if it comes in this week, i am planning on swapping it Friday on my day off or the weekend.. If you wanna help that would be great.

 

I've had the same problem with the work truck. Originally it started when 3/4 of the tank had been used. Just before the pump went out I could only use half a tank before it acted up. Good luck.

 

ya mine is starting to get worse... WOT is fine, but my VE table looks rather retarded in the 95kpa+ ranges...

 

That might work with the tires off, otherwise the bed will hit the tires.

 

lol, i did not even think about the tires.... So isn't it just a couple of bolts and disconnecting the rear harness and the bed comes off?