I have a 1994 Chevy S10 Blazer that has run pretty well for me. It has a 4.3 liter engine. I do regular maintenance and have never had a serious problem. Out of the blue a couple of months ago it started running like crap. It has a rough idle and a serious miss when I am on the road. I pulled out from a stop sign crossing 4 lanes of traffic and it backfired and almost quit on me! I had to nurse it across all that traffic and made it to the side of the road. It died and then started up, and although it ran horribly, I did make it home. I have replaced plugs, plug wires, distributer and rotor, fuel filter and checked the firing order. I had the exhaust and converter replaced to no avail. I also replaced the EGR valve and the coil. It ran fine one day and overnight it started acting up. Any help would be greatly appreciated. I'm new to the website and this is my first question. I'm a 44 yr old woman and have done my own mechanic work except for major work like overhauls etc. But I'm stumped. Thanks in advance.

. Check for codes.

. Replace the Ignition Control Module (ICM). Here's what it may look like and cost:

Zip Code Entry at PartsAmerica.com (http://www.partsamerica.com/ProductList.aspx?PartType=194&PTSet=A&SearchFor=Ignition+Module%2fControl+Unit)

Parts America doesn't show a 4.3L engine for your Blazer. ICMs are very problematic, breaking down due to age and heat.

. Test/replace the coil.

AutoZone can test both of these items for free.

. If the problem persists, test/replace the MAP Sensor.