My 99 Blazer S10 bogs down on highway and dies. Just purchased and prior owner had it sitting in garage for several months. Can't get it to start again. Then it will start the next day. New fuel pump. Fuel pressure stays at 50psi with engine on and off. Replaced fuel relay switch. New battery and cables. Worked for 2 days all over town, then did it again when accelerated up to 60 mph. Had to tow home.
Needs new cat. Any suggestions?

 

Well, do you have any trouble codes? Next time it happens, carry a spare spark plug and check for spark. If you have spark, maybe a fuel filter clogging while driving then settling when the engine isn't running. If you have no spark, it could be a lot of things. Crank sensor?