Blazer Forum - Chevy Blazer Forums - 1995 Chevy S10 Blazer

I have a 1995 Chevy S10 Blazer which has 175,000 miles on it. The vehicle is in show room condition but recent machanical problems causing concern. It had an issue of when in gear at low speeds (10-20 mph) the RPMs would suddenly drop to 200, the vehicle would vibrate violently and there was no power when stepping on the gas. Once pulling the vehicle over, I would put it in park, turn the engine off and restart it and it would run fine. This problem was intermittent. Mechnic said the spider needed to be replaced. Replaced the spider, distributor, cap, plugs and reset timing. Ran fine for two weeks and has now started to do this again. Now, however, it does it at all speeds. It also seems to experience rough in gear idle andrough acceleration from stop. Someone told me it might be the fuel pump because gas gadge is messed up. Been into dealer twice for a week each time and they could not recreate, so they could not diagnose or fix. I don't want to throw away money chasing this but don't want to replace vehicle either. Any suggestions?????