strange loss of power on 86 Caravan

[afroney]

Hi, I have a 1986 Dodge Caravan with a 2.6 Mitsubishi engine. My problem is that the car will suddenly lose power while driving down the interstate (65mph+). I am not hearing any sputtering, the speed just smoothly drops to around 35-45mph and will hang there for 5-10 minutes with my foot on the floor. If I contunie to leave it floored, the van will eventually return to normal, and then start the cycle again at a later time. I can stop the car, wait for 5 minutes and restart; it will start fine, and contiune going normally from there. I have replaced the fuel filter, spark plugs, spark plug wires, distributor cap and rotor. Voltage is reading normal throughout the entire time, so I know its not a loss of voltage causing this. Im completly stumped at what this probem could possibly be. Any help would be appreciated. Thanks!

[zedward1]

Originally Posted by afroney

Hi, I have a 1986 Dodge Caravan with a 2.6 Mitsubishi engine. My problem is that the car will suddenly lose power while driving down the interstate (65mph+). I am not hearing any sputtering, the speed just smoothly drops to around 35-45mph and will hang there for 5-10 minutes with my foot on the floor. If I contunie to leave it floored, the van will eventually return to normal, and then start the cycle again at a later time. I can stop the car, wait for 5 minutes and restart; it will start fine, and contiune going normally from there. I have replaced the fuel filter, spark plugs, spark plug wires, distributor cap and rotor. Voltage is reading normal throughout the entire time, so I know its not a loss of voltage causing this. Im completly stumped at what this probem could possibly be. Any help would be appreciated. Thanks!

How's it goin', eh?
This sounds to me like carburator icing. Is it cold were you live? When this happens again, check under the hood and look into your carburator. If you see ICE CHRYSTALS all around your venturi (the round thing held in the center of the carb right at the inlet of the carb).If it looks like it's coated in white fur, then you have a problem with the air intake heating system.
There is a flapper in the air box(where the air filter sits) inlet that ducts hot air from your exhast manifold to the inlet of the carb when it's cold out. This flapper will then close to duct cold air into the engine when it's warmed up.
Check to see if the hose (cardboard tube with spiral wire suppuort) is disconnected from the metal shield that covers the exhaust manifold (this collects heat under it). My shield was rotted away and gone when I looked at mine.
This is the source of hot air for your cold engine. It uses this air when a sensor says the air comming in is too cold.
The symptoms are as you describe. The engine off and sitting for 5 minutes will melt the ice and everything is fine again.
Hope this long-winded info is what you need.
Cheers, Eddie the Cannuck