Stalls on quick throttle, low end power loss?

[1991SHOnewb]

Ok. Had a bunch of issues with this 90 MTX SHO. Finally got everything fixed except one driveability issue. If you are at idle and you goose the throttle the car will bog down and stall, or barely recover, 90% of the time. Tried running KOER test and car stalls midway through when the controller tries to do something with the RPMs. KOEO test reveals no codes. No check engine light ever sets while driving either. Tried unplugging the MAF, but there is little change cept the check engine light then comes on. Checked the TPS and its at .96V and has a steady increase in V while moving the peddle to WOT. Oh yeah and the car seems pretty doggy until the secondaries kick in. Could be just my imagination. So I'm hoping theres still some old SHO pros out there that can help. Thx

 

[Sho_Stopper_07]

it could be a number of things, first of all, have you recently done a tune-up on the car? or does it have plugs that you used 200K miles ago? lol

because foweled plugs could be 1 reason. or plugged cat, maybe fuel filter.

 

[F-22 Raptor SHO]

1: visually check to see of the secondaries are opening when you give it WOT...look under the hood as you manually raise rpms at the TB by hand and look for the secondary hinges to move when rpms reach more than 4000.

2: check fuel pressure at the rail during idle...should be 30 or more...WOT is 40 psi

 

[1991SHOnewb]

Brand new motorcraft plugs. Newer wires 20K miles or so. And yes secondaries open at 4k RPM. Ran fuel injector cleaner through system also to try to clear it up. No change. Any other suggestions?

 

[92inPA]

Two possibilities come to my mind. A) A sticking IAB, or B) clogged fuel injectors. If the injectors are REALLY plugged up, no amount of fuel additives will help. You would need to remove the injectors and send them out for cleaning, or replacement.

I had very similar symptoms in my 95 mtx about a year ago. Everything I checked seemed fine. Out of frustration I installed a spare set of injectors and that turned out to be the cure.