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backfiring, popping

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ok so heres the problem. first if cold it takes at least twice to keep the car going after starting. once it can run on its own the problem really turns on. if i floor it, it bogs down insteda of revving up(also does this if im cruising). once its idling and im ready to go it sputters bad. i have to really baby it for about 5-10 minutes to get it to act normal. once its warm it does okay. it wont accelerate to its potential and i cant get it past 3500 rpm. so heres what i have. gt-40 engine. cobra intake, cai, 75mm maf(cal for 19lb inj) and 75mm tb, shortys, off-road h pipe, flowmaster 40s. what ive checked so far-maf, iac, vac leaks, timing, fuel filter, fuel pres reg, full tune up. im not sure where to go next. maybe fuel pump. im at a loss now. thanks in advance.

I'm not too schooled with the 87's, but it sounds like you have either a fuel delivery problem when it's cold or what we old carb guys would say is that you have a choke problem not activating.  How does that EFI restrict the cold air from getting into the fuel induction at startup?  I would assume it would be the MAF or MAP, but not sure. 

yeah i thought maf also but i put it in about 9 months ago and this problem started about 3 months ago or so. i pulled codes but its been so ling im not sure what they were. i guess i will run them ago.

have you tried cleaning the maf??

i pulled codes and got 12-isc out of range, and 21-collant temp or coolant temp sensor out of range. my ques is would the cool temp sensor cause the backfiring. i actually havent cleaned the maf because it looked okay but i will spray it down.


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