92 Previa Cold Engine Miss

[leanscribe]

I drive a 1992 AllTrac with a 5-speed standard transmission, 148K
miles. When the engine is cold (even in dry weather with an outdoor temp in the
70s, like today), the engine sputters and misses like it is running on 3
cylinders. It will continue to miss even after the engine is warmed
up, until I park and turn the engine off. If I wait 15 minutes,
then restart, the miss is 98% gone, and the engine is running on all
four.
If I leave the Previa parked for 3 hours and restart, the result is
the same, the car runs okay. Left all day or overnight, the miss
returns.

Most of the fixes that I would normally try (plug wires, distributor
cap, rotor, plugs) would apply for a persistent miss. If the miss
were related to cold engine temperature, I would expect the miss to
go away while I was driving, after the engine warmed up. It doesn't.

The Check Engine light is off. Has anyone else experienced these
particular symptoms?

[previa92le]

While your logic is good, I had a plug wire (#2) conductor separate and it caused intermittent problems, mostly with acceleration (sometimes the engine would miss during acceleration but sometimes just idling along would be troublesome).

I'm voting on the items you listed as places to start, especially if it's been more than say 80K miles since you did a "tune-up".

Wm, 92LE, 199.5K miles

[leanscribe]

When I inspected the distributor cap and plug wires, I found a gap inside the extender that snaps onto the spark plug for cylinder number 3. The arcing inside the extender had degraded the silicon conductor to carbon. The silicon wires, because they are so susceptible to breaks in continuity, were at the top of my list of suspect components. It's great to be running on all four again!