I’ve got a cold idling problem that has crept up recently. There is no problem with idling when the engine is warm.
At first start in the morning when the engine is cold it starts normally and idles normally for six seconds then drops to 500-600 rpm then speeds up to 1,000 rpm then after six seconds it drops to 600 rpm then to 1,000 then slowly drops back down 500-600 then up again around 1,000. If I don’t touch anything after 25 seconds it will slow down to 500 rpm and then die.
After it dies I can hear the Frequency Valve (102395) buzzing like a mad hornet on the passenger side valve cover and it stops after two seconds.
When I immediately start it up again it does the same thing all over and dies after about 25 seconds.
I can depress the gas pedal to prevent it dieing but I need to hold the pedal for about a minute then it’s warmed up enough so that it doesn’t slow down and die on its own.
Things I’ve done to try and fix the problem. I lifted the inlet manifold and replaced the Constant Idle Switch, Thermister (102480). That didn’t fix the problem.
Then I removed the Idle/Low Speed Motor (102502) and cleaned the air passageway with brake clean and paper towels until it was clean and the mechanism inside rotates smoothly then I reinstalled it and I still have the cold idle problem.
Then I removed the Warm Up Regulator (102353) and disconnected the two fuel lines and removed the bottom cover plate and the insides look perfectly normal and no burned wires. I made sure the filter screen is clear of any debris. After reinstalling that didn’t fix the problem either.
I am at a loss of what to do next?