What gives I pulled out the 4.8 auto and put in a lq9 6 speed in , the motor has a 226/226 .585/.585 on 112 lsa, ls6 intake, 42lbsvo's , longtubes, no cats, 6 speed 4.56 gears. something is not right, its a rcsb truck when I'm in 5th and 6th gear it is missfireing. My stock fuel pump should support it right?? Maybe I should change plugs? I will call Jesse tomorrow and see what he says about the tune. Whatta you guys think?

 

i would check that pump, might not be enough, mine wasnt! but given your mods its probably a tuning issue. Any ses lights?

Did you install your fans?

 

Yeah I got the fans in too I had to lenghten the wire going to the computer a little,but it worked flawless. No ses light,what plugs should I run?

 

cool man, gla ya got em goin.
NGK TR55's work well! Thats what i run

 

Right now my truck wouldnt run a 13.50 with parish's truck pushing it, I hope its just the tune, and for safe measure I will probably do the 255lph mod.

 

yea, i would. Its a cheap and easy mod at a little over 100 bucks.

 

If you installed all these mods at one time, then it likely your tune. You cant run larger injectors without tuning for them.

 

if your truck runs strong through the rpms then its not you fuel pump it should be cutting out around 4-6k rpms if it was a pump. if its only really missing in 5th and 6th gear then it sounds like an ignition problem. like plugs or wires.

 

Something's definitely wrong cause you should be making almost twice the hp as before with that combo. I would recommend using only the OEM iridium plugs but it's not going to make that much difference. I would think it's a tune or fuel issue... maybe rockers incorrectly torqued and lose or adjustable rockers incorrect with valves hanging open. Is there any excessive valvetrain noise?

 

is it a mail order tune?? if so more than likely its the tune..get a dyno tune man its so much better and no guess work for jesse or nelson or who ever does them..not knocking them down they are realky good at what they do, but for the mods you got its kinda hard to guess the right numbers in your tune...hell i may spend an hour or all day tuning vehicles..i dont see how some one can get it right the first time..