check fuel filter, air filter, and spark. if that's ok start looking at sensors
for a better answer, would need more info
The choke mechanism on your 98 Explorer could be sticking. The EGR valve could also not be functioning right. Either of these issues could cause the rough idle problem.
head gasket is gone
Yes
Computer needs to re-learn the idle. Spark plugs are bad. Valves are not properly gapped. Adjust Idle Speed on Throttle body.
The idle speed is computer controlled
usually caused by throttle position sensor, also can be caused by either low fuel pressure, fuel injectors must have specific pressure to properly operate at running idle, this can also be caused by clogged fuel filter.
Idle is controlled by the ECM (computer). Not adjustable. check sensors
The most common reason for a vehicle to run rough when it is cold is bad spark plugs or bad spark plug wires. Change the spark plugs and spark plug wires.
I had the same problem with my 98 jimmy I repalaced the water pump have had heat since.
It is not adjustable. If the idle speed is not correct, then you have a sensor/actuator/computer issue.
Get the throttle checked.
Jimmy Kimmel Live - 2003 1-98 was released on: USA: 6 June 2003