Chevrolet Repair: engine light..., chevy s10 blazer, s10 blazer

Question
Hi,
I have a 93 Chevy S10 blazer 4.3 Vortec auto 4x4. It has the CEL on/off lately for the past two months. I get a code 32, baro sensor(MAP sensor), EGR or egr evrv, something to that effect. I replaced the MAP sensor a few times already with used units. Each did nothing. I changed the EGR with another used one and no different. Still get the code 32. It runs well at times, then the CEL comes on and it runs like dog poo wanting to stall out whenever I slow down and the idle lopes. If I keep the gas on it, it'll maintain, but otherwise not. I could get new parts, but want to be sure of what it is first and now I'm not. I keep coming back to the same code. Any tests I can do to confirm one or the other?
Thank you.

Answer
Hi Mike.... if you are getting a code 32 it is a map sensor problem...if you want to know for sure you need to put a scan toll on the truck and watch the voltage values as the truck is running, compare them with the values the it should be for your area...values are different depending on where you live...IE: mountains are different than sea level. if not within the values where you live replace it...you should be able to get the chart off the internet...another common problem with those engines are air leaks in the intake or vacum lines...check all vacum lines for crackes and replace the ones that are bad. for intake leaks you can use a good air intake cleaner and spray around the intake area when running and see if the engine revs up while spraying..if it does you may have a leak.... hope this helps