Popping and Starting Problem, NEED HELP

b1gp1mp1n247 said:

i also wanted to add that it is a 90 GT 302, shorty headers, o/r h-pipe, CAI, Motorsport Wires, Bosch +4 plugs. i dont know if any of that will make a difference but i just wanted to add that in just in case it would

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my 87lx did the same thing turned out to be o2 sensors make sure to change both of them

when you start the car, it is in open loop. it uses preprogrammed maps to meter fuel. once warm, it goes into closed loop, which then incorporates the O2's. when cold, and when you have problems, the O2's are not used.

how long have you run the Bosch plugs (arent plus 4's platinum?)? some foxes dont like platinum. they idle low and cut out at higher rpm. platinum does not conduct or run as hot as copper.

i would investigate the vac lines further. popping and cutting out can happen when a leak is present.
check for codes too (even if the CEL is not on, codes can be stored in KAM).
i would check the values of the ECT. if it is telling the puter that the car is warm, the mixture will be too lean. same symptoms as a vac leak. the sensor can read within acceptable range to not toss a code, but if it is telling the puter the car is warm, that is not good.
good luck.

i am not personally a fan of doing mods when the car is sick. makes more variables, IMHO, if the problem does not fix itself.

i would be lookin for a vacuum leak. you have the same idea, since you say you may be lean. vac leaks cause leanness and are more problematic on cold motors. you should have 16-20" of vac at idle.