Just got home (had my truck towed home since it is running worse by the minute). Ryan Thanks again on taking time to do that, and it did help rule out different possibilities. Like you mentioned Charlie is pretty sure its the fuel pump.

We were both under the truck looking for leaks and nothing found....the truck just loses all power after quarter throttle

 

Just make sure to put it under a load while testing the pressure again
If it was a tune issue this would have started happening immediatly after the pcm install or shortly after,that pcm has been in the truck for about 6 months or so.
When things just start happening more than likley mechanical.

 

I was figuring it being something mechanical or electrical. Just wish my fuel pressure gauge had a long enough hose that we could have used it while driving.

 

Check or replace your o2 sensors front ones I had the same problem too once already also you might want to clean or check or replace MAF...........I also had to replace the MAF too later after I change the o2 sensors............symptoms the truck had i would be driving @ 40mph and the rpms were in the sky and it had terrible IDLE

 

I don't think those are the problems here. The O2's look to be switching fine in the log and the MAF readings are in-line with what I think they should be. We did clean the MAF and it didn't help any. Also it idles ok, maybe a little rough with the cam but overall not bad. The problems don't really start until he starts driving it.

 

im just throwing it out there,,,,, maybe a cracked/broken spring? thats how mine acted before i dropped a valve...

 

You know I was thinking the same thing as a possibility, since it is backfiring through the exhaust and he says it sounds different. I just didn't think it would idle very well with a broken spring, or that the cylinder balance would have shown something. I guess if the spring is just cracked then it might only start causing problems at higher RPM's. It sure couldn't hurt to pull the valve covers and check. I would hate for him to start replacing parts only to find out it was something else.

 

yup but i would hate for him to finally break a spring and drop a valve and break a piston and scuff the cyclinder wall, and the motor will be messed up like what happened to me last month... so now im replacing the whole motor due to a damn spring.... but hey, it might be a good upgrade for him...

 

He does have 918's, which ones......

 

I don't know but if it is the older ones I would be checking them out for sure.