Possibly a tip or resolution to your EFI engine issues:

1996 Camaro 3.8L

Misfire, Bucking, Loss of Power, Ping, Higher Engine Temps, Fuel Economy,
Sputtering.

Despite a "positive" fuel pressure test at idle and half throttle (unloaded), I had
always attributed the above symptoms as a combination of ignition, and EGR
related issues.

After replacing my fuel pump last night, all of the above symptoms are
GONE!

Hindsight is 20/20 as they say, and now looking back I can conclude that
a weak fuel pump could have been the root to all of those issues.

If the pump is not able to sustain/maintain adequate fuel pressure at RPM
above 3000 (under load), the air / fuel ratio would go lean causing a hotter
combustion temp.

That would explain the higher engine temps, pinging and poor fuel economy
which are also close cousins to a faulty EGR circuit.

A better test would have been to drive around the highway and/or taken
wide open throttle passes with fuel guage strapped to my windshield.

That may not have postponed the inevitable ignition parts replacement; but
it would have saved my brain from 'confusion overload' over the last two
months.

There's your tip from a fellow Fbody friend. Don't rule out the fuel pump
under those conditions...and be sure to test the pump under load at WOT
because we all know the engine requirements change under load.

 

I have done that, quite literally on MANY cars (do a search on my posts related to carburetors and you will see I recommend this test over and over again to everyone who asks). Cops who pull you over want to know exactly why you have a gague duck-taped to your windshield (usually they think it's something evil related to a nitrous system), but I've gotten quite good at having that conversation with them. All my fuel pressure gagues have about 5' of extra hose patched in between the fitting and the gague head- and that's exactly why.

Fuel pressure at idle in the driveway is almost meaningless. You gotta see it at WOT at high RPMs to know for sure if the fuel system is keeping up with engine demand.

Glad to hear you nailed it dead-bang.

 

haha same happned to me after my 396 build i bought the new pump but was just testing the motor same **** changed the pump good as new