my 1993 astro van has 75000 miles now it seams to run on 4 cyl in the morning for about 5 min then runs ok on all 6 cyl. and it also has a very bad miss when i step on the gas. sometimes and it's getting worse hope someone can help thank you
If it's only been driven 6k miles a year, I bet the fuel system could use a good cleanout, and the ignition would probably love a complete tuneup. Throw in a can/bottle of injector cleaner at your next full tank fill-up. Expect it to run like cvrap for a little while until all the snot is cleaned out of it - maybe half the tank of gas worth of driving.
Have you had it tested on a code reader for ignition errors? Lots of auto parts stores will do it for free so they can sell you the parts to fix it. Even if you don't buy the parts, the test is still free. Call around.
13 year old engine with 75k on it? Wow, that's not used much is it? Or is that on just the engine?
A hard multi-cylinder miss from a 4.3 V6 would make me first suspect cap and rotor breakdown. They're not too hard to get to. Just remove the 'doghouse' inside the van and voila, the back of the engine is quite accessible. Use quality parts if you decide to replace them. I've had good luck with Standard's best line (just personal experience, not a plug).
Another thought: Is this a 'Vortec' V6? I didn't think they were available in 1993 on the Astro/Safari, but maybe they were...
In this case, you could have sticking injector poppets - common on the Vortec fuel injection design. They frequently will fail in such a way that they stick closed in any number of cylinders after an overnight cold-soak. A shop may be able to free them with an injector cleaning service if this is the problem.
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