hi there fellas. my '86 automoatic chevy blazer has started started giving me trouble. it's making a noise like it's mis-firing or something and a lovely knocking noise comes from under the hood. my diagnostics say that it's the speed cencor circuit and the barometric pressure circuit. i went out and bought a manual (chilton) for the darn thing but it doesn't tell me where they are.... i just put on new plugs, wires, oil filter, belts, and an air filter. i'd be grateful for any help i could get. thanks!

1993 Ply Grand voyager SE.........Transman2U helped me solve my problem with this van last year. I had the transmission rebuilt in 2001. Then mechanical problems began. I spent over $1800 having it towed and new parts put on it. The dealership just kept putting new things on that didn't fix the problem. Transman2U said it was probably crank position sensor since I had transmission work. My hubby put one on and the problem was fixed in August last year. The van has been as good as when I bought it until this morning. While driving about 45 mph it jerked very hard. ( So hard my daughter thought I had hit something.) From that jerk it would not upshift. I drove about 30 mph to a parking lot. Before I had transmission rebuilt in 2001 it did this exact same thing. So I remembered the remedy I had used for months back then. I pulled over turned van off and sat for about a minute. Then restarted and drove back home approx. 10 miles with no problems. In 2001 the repair guy said this reset my computer turning it off and then back on. So my question is : Is my transmission going out again or could it be a sensor or computer problem? If you reread my posts last year you will note that the transmission repair guy had a horrible time getting the transmission fixed. He even told me to drive it for a while and it would probably get better!! I really don't want to go through that again. PLEASE Help...................very discouraged!!!