I noticed this a few months ago, my 97 blazer seems like its kind of jumpy one I get going around 50-60mph. The engine seems like it kind of kick in and out really fast. The RMP gauge will suddenly drop the go back up again really fast. I am not too smart with cars and stuff so I dont really know what would be going on. My engine is a v6 vortec. Is this something I should take it in for? Thanks.

 

Do a fuel pressure test.. First place to start, we'll go from there.

 

Thought I would jump into this thread as Im having a similar issue. 98 v6 w/311k miles. Ive read most of loss of power and bogging threads but havent been able to correct mine. Idles and runs good until 2000k + rpms. dosent matter if shes under a load or not. Fuel pressure @ 59 and holds to 54, new plugs,wires,cap.rotor just today a new MAF and still wont accel. stumbles and backfires. Repl the fuel inj spider about 75k ago for a random misfire code and ran well. Could perhaps I need to do it again? vacume seems sealed good as I dont hear any leaks, sprayed tb cleaner around the plenum and no change in rps. Also did a TPS last week. I hate to keep throwing coin at her...but I want to give it to my son in June.
Anyhow, any help would be well recieved! BTW great forum. lots of really good info here thanks to well informed techs. Thanks for your help.