im asking this for a friend:

-2004 singlecab
-texas speed and performance engine (dont know the specs)
-jake performance t400 transsmission
-88mm turbo

truck is built recently and it launches great but once about it hits around 5400rpm it starts popping and missing and doesnt want to go above 5400

so far:
-plugs have been changed 2 times
-new msd wires
-tuner said injectors seem like doing good in hp tuners data
-cam sensor and sprockets have been changed

its a well known tuner so i dont think its the tune

any ideas would be appreciated, if any other info needed i can get it, thank you in advance

 

How much boost?
Stock valve springs?
What plugs and gap?
AFR?
Timing?
What fuel? Meth?

 

no meth, c16

truck made 1006 rwhp and worked great on the dyno couple months ago, then some times it did this, then worked great again now it will just always do this

my friend just told me he relocated the battery to the rear in the box, could a lose ground make this problem?

 

It could be a grounding issue, but what plugs and what gap?

 

check your fuel injector duty cycle when it gets to 5400 might be putting in too much fuel. Had that problem with a vette when we added bigger injectors...Scaled them to spec but still had to continue to pull fuel until it started clearing up. It would hit a wall at like 4800 rpm and act like a rev limiter. Think my buddy ended up pulling 80% of fuel and fixed it.

 

5671a-10 at 20 gap

 

Whats the wideband say? Ill never understand why some guys will put in $20k into the engine/trans/turbo but wont buy a $200 gauge to make sire it wont blow up.

 

I see a Lingenfelter LNC002 in your sig. Did this problem start after installing it? I think I remember somebody having a similar problem, I'd try removing it.

Edit: just realized you said it's a friend's truck, not yours. Sorry...

 

I am having a similar issue lately. I was going to check my crank sensor to make sure it is getting a good signal. Is he running a billet reluctor wheel?

 

Just got some more info:
Air fuel is at 11.5-11.8......
11.8 airfuel. 15 degree timing 80% duty cycle.... 20-24 psi