Help needed from all knowing GURU's

[DRK]

The car has performer 5.0 heads, cobra intake, e- cam, 24lbs inj, 73mm C&L, a 9# powerdyne w/ 8:1 fmu., and 13 degrees intial timing w/ no retard. Base fuel pressure is 38 w/ line plugged.
It was on a pull around (on a goose neck) Dyno the other day with a wideband tail sniffer. The A/F was 17:1 down low 2800 and dropped steadily with RPM, it was 12.5:1 buy 4000 and 10:something by 5700 at 7#s of boost and 70psi fuel pressure.
My friend just bought this about a month ago and has been trying to figure out why it runs so bad at part throttle (like it's got the hiccups)... BINGO.
What would cause this?... Bad mass Air sensor? Bad O2s? Bad BAP?combination of things????
It has more then enough fuel up top, it idles very rich, and raising base fuel pressure makes it runs very rich.

BTW it made 387hp and 403tq

Thanks

[Jesse James]

TPS voltage sounds like. Bucking at low rpm and under WOT until you reach higher rpms? I had a similar setup years ago, similar issues.
1.My TPS was out to lunch. I had to drill the mounting holes slightly in the throttle body to get the TPS voltage right, "there may be enough play without drilling I had a Ford Racing 65mm TB.
2.One catalytic converter was toast. Ended up replacing cats , changed my FMU diaphram a few times can't remember what I ended up with, similar dyno numbers. Hope this helps some, been a while.

TPS is a good place to start.

What kind of fuel pump are you running with your setup. I had a 190 in tank and the inline pump that came with the blower. My fuel pressure was a bit higher under WOT.

What size rockers are you using with those heads? 1.6, 1.7?

Good Luck :cool:

[DRK]

Thanks we'll check it out.

[sacstoy02gt]

After I installed my KB, it would hiccup and miss at part throttle. WOT was fine. Turned out to be an o2 sensor. My driver's side bank o2 was reading slow, so it was dumping more fuel on that side, causing it to hiccup. Changed the o2 sensor and it's been running great for the last 1800 miles.