Misfire when cold, but fine after 5 minutes of driving.

[chauqg]

I own 95 aerostar xlt, lately when engine is cold there is a serious miss only in high gears. Down shifting (electronic) solves the problem. Warming up in 5 minutes does also. Any thoughts on Plugs? wires? rotor, dist cap etc.? I hear it is a bear to tune up and I'm not the most talented and do not have unlimited $$ - I could not remove the engine cover in the drivers compartment... Need lots of help .... Any Suggestions welcome!

THANKS

Chauqg

 

[BrooklynBay]

Welcome to this forum! I've renamed your thread, and moved it into the Aerostar section. It might be more of a transmission issue than an engine misfire issue. Could you add 1995 next to where it says Aerostar in your profile? I think your problem sounds like a sticking transmission governor. Do you have a delayed 1-2 shift when it's cold? Check # 45 in my list of useful threads for more information: http://www.explorerforum.com/forums/showthread.php?t=155582

 

[steelhead48]

chaqg,
probably an engine under load miss.
only when cold indicates probable problem with ECT, Engine Coolant Temp sensor, failed and not indicating to engine computer that coolant is cold, turn on rich air/fuel mix until warm.

ECT testing procedure if you're handy with a DVM or just replace, they're low cost and easy to change. common engine control sensor failure.
2 wire sensor screwed into coolant system near and above water pump, which engine?
http://fordfuelinjection.com/index.php?p=28

Cliff