1999 Chevy Astro Miss when cold

1999 CHEVROLET ASTRO
247,583 MILES • 6 CYL • 2WD • AUTOMATIC
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SAMPHOTO
  • MEMBER
  • 2 POSTS
Some days... 1 out of 6 van will miss in morning
high humidity & rainy days van will miss for sure.
9 times out of 10 goes away after warm up.
coil has been replaced recently.
doesn't throw off any codes.
fuel pump replaced 2 yrs ago
plugs and wires ok
I'm planning on a compression test
and a fuel pressure test this weekend
possibly a scope check.
any ideas ?
Oct 13, 2009 at 3:59 PM
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JACOBANDNICKOLAS
  • ✓ASE Certified Mechanic
  • 110,194 POSTS
  • ASE Certified Mechanic
My first guess when you say it is worse on damp days is either the distributor cap or plug wires. You said they were okay. How did you check them?
Nov 18, 2009 at 10:30 AM
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SAMPHOTO
  • MEMBER
  • 2 POSTS
The plug wires were replaced 6 months ago
after 1 came apart in my hand. new duralast installed

high condensation areas seem to play a part.
I just drove from a heavy fog area and it missed all day. [ 5 hrs of driving ]

>>>It does not miss under acceleration.
It will miss immediately after letting off gas
and while cruising. <<<

Twice it has missed all day. Both times on long road trips. Normally driving around town it will miss for 20 minutes in the morning and run fine after that.
Most other days it will not miss at all.

I have installed a new dist cap so I'll wait and see.

I did not see any cracks in the old dist cap

Ignition module and crank sensor are recent.
`
thanks for your help
Nov 24, 2009 at 3:20 PM
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