engine miss and back fire at part throttle

i have a 90 5.0 5 speed (originaly an automatic) with an F303 cam, explorer intake, stock heads (shaved .030) new valve job and springs, egr delete kit, smog pump deleted, A/C & power steering deleted, all vac ports plugged except fuel pressure reg & brake booster. summit long tube headers, ORH pipe W/ flowmasters, base timing set at 17 degrees. New plugs, wire, cap & rotor. I checked for vac leaks with engine running with starting fluid & found nothing. No check eng light while driving but checked for codes any way. 11 came up in KOEO. 12 94 44 33 in KOER. after that I did the cyl balance test & got 9 (system ok). The eng dosent want to stay running by its self until it warms up a bit. while driving for example, once i shift into second and start to accelerate slowly, it will studder. give a litlle more throttle & it might back fire a couple times. a little more throttle and it starts to smoth out around 2000 RPM. i dont think this is related to the new F303 cam because the car was doing this before also. any other helpful hints would be great. thanks

with regard to the egr, i have one of those kits you can buy off ebay that comes with a blockoff plate & a resister that is supposed to tell the computer that the egr is staying closed and the computer is supposed to adjust for that. (so they say lol) i thought that egr might have been the problem before because, the guy i bought the car from bloked off the hose but left the egr on the car. after ditching the egr nothing changed. thanks for the tip though. i found the surging idle check list on the forum. going to check TPS & IAC tomorrow. thanks again

I run only 93 octane. no problem with detonation as far as i can tell. replaced the tps today. that seemed to take care of the low rpm issue. funny that it didnt set the check eng light off though. that surging check list is awesome. think i will take the iac off and try cleaning it in the near future. thanks again for the tips.