OK, anybody want a challenge? Problems...

[1987Rock]

Ok, first off, this isn't my car, it's a buddy's. I didn't have time to diagnose anything cuz I left town for the weekend. He doesn't know anything about cars except how to drive them, so I'm trying to help him out. Just trying to get some ideas about the problem
I only have limited info right now...his parents have the rest, this is all he had

Ok, the car: 1995 Rio Red Cobra 5.0 5-speed
stock bottom end as far as we know
TF Twisted Wedge heads
Trickflow Stage 1 Cam
Stock Cobra intake
3/8 Phenolic spacer
ARP head bolts
double row timing chain
1.6 race roller rockers (don't know what kind)
underdrives
255 LPH fuel pump
3.73 gears
LTs, X-pipe, flows with dumps
Vortech super charger (not hooked up cuz it needs a rebuild)
MSD 6AL box 6500 chip
bigger injectors (looked red)
I assume it's got a fuel pressure regulator on it (couldn't see it)
He recently got it retuned to run without the blower (apparently the did a horrible job)

He took me for a ride in it and if it's just idling or just part throttle cruising, it's ok. But when he jumps on it, it acts like it loads up real bad and doesn't wanna go...and then when he downshifted from 3rd to 2nd about 35-40mph, it back fired real bad (really really really loud with dumps!!!)

Like I said, I'm not looking for a definite answer, just looking for some ideas from you guys. I know we need to check the timing, and the fuel pressure and vacuum, but any ideas before we start work next week would be great
Thanks guys!!! :SNSign:

 

[94-302-vert]

Sounds like either a bad tune OR poor spark causing it to load up...

Since you mention the tune was just redone I would think the tune is too rich.

 

[ProKiller]

are you sure they retuned it for the nonblower combo?

 

[1987Rock]

Yeah, they tuned it to run without the blower...it's got an SCT chip in it and according to the receipt, they only worked on it for 2 hours.

I know a tune is the most obvious answer that could fix it all, but what other things non computer related that could contribute to this? Just some things I could check before I send him back to a tuner?

 

[ProKiller]

i can't believe that they would have let the car leave if it was running like that. I would have turned right around and flip $hit on them. again, tune is the most obvious reason. spark and timing is possible. check the timing. is the MAF cal'd for the injectors?

 

[1987Rock]

Like I said, I don't have all the info, only some...but yeah, I hadn't thought about the MAF. Def check that if I can find the info, spark, timing, vaccum, fuel pressure.

Thanks guys! I'll be gettin on this sometime this week, if I find anything, I'll update. :SNSign:

If anybody has anymore idea I'm not thinking of, let me know! I think I'm gonna make him come up to Atlanta and get it tuned at MV Performance, or Modular Powerhouse cuz he's just been going to general tuners in Savannah, Ga.