when u get the car started, after u jump it or whatever. disconnect the positive wire of the battery. if the car dies your alternator is bad. that means your car was running off the battery, thats y your car would be fine when u first start driving it and dies after u have been driving for a while. any auto shop and put the alternator on a meter to see if its good. good luck!!
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89 GT AOD w/ shift kit, B&M rachet shifter, Trickflow intake, Crane (E-type) cam, 70Tb, 75MAF, 1.6 Rockers, Pulleys, MAC headers and H-pipe, Dynomax mufflers, K&N, 3 core radiator, white face gauges, custom interior, cobra R rims
MY89GT