1997 Ford Explorer
Hi, we have a 1997 Explorer 4.0 liter V6 sohc and it has a really annoying cold start problem. It starts, but revs up to 2750 then back down to 750 then back up and down again about 6-7 times, then gradually evens out but remains lumpy. It sometimes drops down to 200 then picks up or cuts out! It restarts fine, but still lumpy. However, we found something that helped was putting a hairdryer (?!) blowing into the center of the top of the engine for about 10-15 mins before trying to start; it then starts and revs about 1500-1700 and is steady and then gradually comes down to about 1000, but it is still lumpy.
We wait until the engine temperature gauge starts to move, and then drive it, but if we rev above 2,000 the engine management light comes on.
We took it to a garage and plugged into diagnostic machine, and it showed engine coolant temperature sensor, which we replaced, however, it made no difference.
Any ideas please? We do live in UK, so most Ford garages 'have no idea' unfortunately.It does run beautifully when warmed up and restarts fine during the day, it is just first thing in the morning. My husband is a mechanic so can do most anything that needs doing but we have no idea what it is that needs doing!