Hello, Please suggest a cause/solution to the following:
1993 Chevy Lumnia APV 3.1 L engineIn the summer, when the van engine cold, it starts OK. After 10-15 seconds, the idle drops way down, almost to the point where the engine dies out. Then, without human intervention, the engine revs up to a high RPM. This cycle will continue until the engine gets to normal operating temperature.
If you drive the van before the engine reaches normal operating temperature, a similar thing occurs. Driving along with steady pressure on the gas pedal, the engine would rev up very high, then return to normal. Other times while driving along with steady pressure on the gas pedal, the engine feels like it will die out. Sometimes, when driving along you want to speed up and go to step on the gas slightly, the engine nearly cuts out before revving up.
Occasionally, the van stalls when going around corners (foot not on gas pedal).
Once the engine reaches normal operating temperature, everything is OK.
In winter, the above happens when the van is started when the engine is slightly warm, like after you have been in a store for an hour or two. However, when you start the van first thing in the morning or after being at work all day, everything works fine.
Air cleaner is clean. Fuel filter was changed about 2 years ago. Spark plugs & wires changed about a year ago.