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· Registered
107 Posts
Discussion Starter · #1 ·
hey all,

newb here, pre thanks for the welcomes below!

96 astro, 4.3, etc, 148k.
im the 2nd owner of, my dad was the orig. about 4 years and 30k ago the van developed a weird misfire.
i have replaced most things in the 100k+ mileage turn that went bad, o2's, muffler (2x), cap-rotor-wire-plug (2x), etc.
alternator (2x- the 2nd one failed at 3k miles after replaced), battery, both power window motors, wiper motor.
new fuel pump & pressure is stable (w/ in specs), new petrol filter.
my chk engine light came on last month (when it was -17º outside) but turned off day later.
have not scanned the computer in the past year or so.

when it rains, the vehicle likes to 'miss' esp in 2nd gear (accelerating). most of the time it goes unnoticed to the passengers, but i can feel it.
when its really wet outside, or when i take the car wash high pressure sprayer to the grille, i get a constant misfire, but no chk engine.
the misfire goes away once the engine dries off, or i keep driving (highway).
the engine runs rough sometimes, subtle shakes in the engine, and other times is smooth as all could be- some days are better than another.

i was thinking along the lines of the mass airflow sens?
searching came up w/ cleaning steps
"Remove the sensor
Remove the 4 torx bolts that hold it together
Take the 3 pieces apart, but note the direction everything goes back together
On the centerpiece, you will see 2 or 3(depending on the model) very small resistors. DO NOT TOUCH THEM WITH FINGERS OR SCREWDRIVER! They are very delicate and will break easily!
Spray them with brake parts cleaner and gently clean them with a Q-tip.(the back side of them will be really dirty)
Assemble the pieces exactly how they came apart and re-install.
Start up the van and be amazed at the power it has now."

i also thought about vaccume leak- when driving w/ vent on (no floor) and i get heavy into the throttle, the vent changes to the floor and stays until the throttle is released. but all controls work, blend, direction. ive checked the lines w/ propane to see if leak but found none, bad one way check valve? vechicle has been doing this almost since we bought it.
most of the mass airflow sens problems seem to be right on key w/ this. just curious about, and wished to step in to forum and see what the group thought.

thanks much!

matt carr

· Registered
5,490 Posts
My first thought is to put a vacuum gauge on it. I'm not looking for a vacuum leak here, just interested in the vacuum readings during idle and cruise.

· Registered
127 Posts
Possibly the coil. A crack in the housing could cause spark issues, especially if wet. Check for carbon tracking on the body of the coil. Fill a spray bottle with water and spray down the ignition components, looking for stray spark. I know you said you replaced the rest of the ignition components, but I would still check them anyway.

· Registered
107 Posts
Discussion Starter · #4 ·
hey guys,

much thanks, very good ideas

-i would be quite curious to see what that vacuum gage would tell me, ill chk the specs
-the coil, very good idea (duh me- get down to the basics), thats an item that has not been replaced, i wonder its status.

great van. ive had mine for about 6 months as my own, bought from my dad after he didnt want it any longer, he had a nice econo car (so did my mom- the astro was used as long haul/tow/mover), the van sat alot. right around when i got my drivers lic my dad bought this van, while i had a 1984 full size g20 (brown) for my 1st vehicle, also purchased from my dad.
heh. me and this van grew up, parents road trips, family trips, airport, vacations, everything. i sold the brown van in 99 when i grad hs, and got a car.
92 sundance, slippy 4 auto trans, it crashed when i was in college, so i picked up a 1991 caprice 9c1 (police), crashed that 2x, replacing the front clip each time (it was a bit more durable/replaceable).
selling the black and white caprice was sad, but it was time, 179k, i bought a 98 crown vic (white) police interceptor in 04 w 51k.
using this as the only, until the van, ive had the time to work on the vic, the front end was trashed, uppers, lowers, all the connectors (centrelink is not a wearable part on them), ive not replaced the lowers yet, its in the garage until its warm. the astro will get some tlc here in the next few weeks, as it warms up.

i like automobiles, thanks for enabling me!

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