Stalling and Backfiring driving on freeway

I recently purchased a 1987 Suburban.

The engin and tranny and most of the stuff under the hood was rebuilt or crate. i have had the vehicle about 2 weeks and had no issues. I was driving into work today and while on the freeway about 30 minutes out the car started backfiring, stalling and loosing driviing power.

No check engine lite, no loss of electrical power. I pulled over, parked the car, popped the hood and saw nothing wrong. Got in started up and it went down the rode a few miles and started right back up. The car stalled out, while rolling i shifted to neutral, restarted her, and she drove for less then a minute and she acted up again. I couldnt get her over 35 mph and was eggsehlling the gas pedal.

any suggestions?

change your temp sensor