94 mustang trouble

[friendsmustangprobs]

The ignition coil is an aftermarket one, i think he said he got it from hypertech or something last year. I will check the voltage output next. The o2 sensors are good, i tested them and compared to specs. Plus it does it when the computer is cool and in open loop also. There are about 130,000 miles on the engine and it is all stock besides the cold air intake, aftermarket coil and plugwires, and a few chrome pieces here and there. How would I check pump volume? the guage only had psi