I believe the top three problems are leaking FI spider'a, leaking intake manifolds, and fuel pumps. I think the issues involving the fuel pump and the Intake Manifold have been addressed already. I don't think the issue of the spider distribution has been mentioned. Starting in 1996 and with the VIN 8th character of 'W', the spider in the intake manifold had poppet valves which would over time get clogged up and leak. Look for a Blazer with a VIN 8th character of 'X' and you will have the new, improved spider fuel distribution system without the poppet valves. By the way, the older style W vehicles can be upgraded for about $200.00 in parts to the newer style FI system. You could do the intake manifold replacement and the spider upgrade at the same time

 

Pitman arm, idler arm, lower ball joints, lower intake gasket, fuel pump, 3rd seat handle likes to break, A/C compressors tend to leak at the seam, distributor gear wears, wiper pulse control board has crap solder joints, oil cooler lines leak.... some of the things off the top of my head.

 

Forgot to add door pins wear out also.

 

ABS vehicle speed sensors (vss). When the vss on transfer case goes out ur ABS lite & engine lite come on. Transmission acts funny as well with vss problem.