Well, I an NOT a mechanic...
but I have read numerous times on the list that this type of problem is
frequently caused by, or contributed to by, poor ground connections.

I suggest that you clean the ground connections well.

Marshall Ruskin

>Hey there...I'm hoping you can help as I am about kill myself.  Rosa (the
>bus) is a 1987 GL with 181k miles.  She exhibits the following symptoms:
>
>Cold Start-Sometimes starts first try but usually takes 6-8 tries to get it
>going.
>
>Hot Start-Always takes 8-10 tries.
>
>Cold Running-Idles fine without load.  Driving idle will occasionally drop
>down to 500 rpm where it will sometimes catch and continue to idle at 800
>rpm or stall.  If it stalls see Cold Start above.
>
>Hot Running-Runs great on highway but will occasionally buck and backfire.
>Last year this bucking and backfiring was rare and turning the bus off and
>then back on cured problem for another couple of months.  Now the bucking
>and backfiring occurs daily.  Also surges, but this doesn't result in
>bucking and misfiring just annoying unevenness.  If Rosa bucks and we
>restart, see Hot Start above.
>
>Work Done:
>Temp Sensor II-Replaced last fall and helped idle problem for a while.
>Idle Stabilizer-Replaced to last fall to cure idle problem (unrelated).
>AFM Harness-Replaced Saturday in attempt to cure intermittent bucking.
>AFM Wiper-Cleaned with wiper with contact cleaner and cleaned inside of AFM
>with carb. cleaner.
>Throttle Body-Cleaned inside carb cleaner.  Check for vacuum leaks-none
>apparent.
>Newer-Plugs, wires, distributor cap and rotor.
>Newer-Fuel pump (unrelated) and fuel filter.
>Newer-Coil (DPO)
>
>Plugs are a nice tan color no deposits, gas mileage within specs, passes
>emission with flying colors (CO mix).
>
>So if you have any ideas on how to help me and Rosa (the bus) out we'd
>really appreciate your time so we can get back to our summer already in
>progress!
>
>Chris P.
>Seattle, WA
>