Misfire with a loss of power.

[Ste_P]

Ford Aerostar - 1995 - 4.0L v6 Auto - 95,000 miles
Hi All,
My name is Steve and I am new in here...
I have the van above and it has recently started playing up.
Initially, running with a heavy load up an extended incline, it has been losing power and slows down steadily. If given too much gas it starts to stutter and loses power altogether, as if it has started missing on one or two cylinders.
This continues until there is a flat or downhill stretch and you can leave your foot off the gas or only touch the gas lightly, then after a little while it seemed to kick back back in and start running 'normally' again.
Last weekend, after dropping out whilst loaded heavily and going up a hill, it didnt kick back in and we had to limp home.
The following day it was running more or less normally again, but was a little lumpy while the engine was cold. This has continued and hasnt gone away.
Up to press this week, I have changed the fuel filter, spark plugs and leads - which has made no noticeable difference. It is getting an air filter, oil and filter change tomorrow - just as a matter of course.
As a side note, the temperature guage never gets to the 'normal' area, it is always showing pretty cold. I have a new thermostat which will be going in tonight / tomorrow.
Any clues?
Best regards
Steve

 

[BrooklynBay]

Welcome to this forum! Clean the MAF sensor, check for vacuum leaks, adjust the kickdown cable, and scan the computer for trouble codes. Do you have a check engine light?

 

[Ste_P]

Thanks for the reply Brooklyn
I will find the MAF sensor and clean it tonight.
The check engine light does come on but its occaisional and intermittent. I couldnt really give a specific circumstance for it coming on - or how long it stays on... Sorry.
Best regards
Steve

 

[BrooklynBay]

You should have a code stored even if the check engine light only turns on for a brief period of time.

 

[Ste_P]

You are a star - thank you
I bought a big can of electrical contact cleaner from home depot ($7), stripped the sensor off (the wires didnt actually look particularly dirty). Gave it a really good dosing of cc with the nozzle almost touching the wires, from a few different angles. Changed the air filter for good measure and threw it all back together. The van is running better than it has for years! No flat spots, no struggle and you can floor the accelerator - she kicks down and goes... (No need for throttle / kickdown cable adjustment )
Wonderful! Thanks again.
Whilst I was in there, I was going to change the thermostat, as that is on my list too - but I ran out of time. Is there any easy way of getting to the little bugger?
And
Do I need to disconnect the batttery for a few secs to clear the fault codes just in case?
Thanks again for your help
Ste

 

[BrooklynBay]

Thanks for the update! You don't have to disconnect the battery since the codes will eventually go away if the computer isn't putting them out. The thermostat is under the thermostat housing. Autozone sells a gasket which doesn't require any adhesive, so that would be a good choice.

 

[speleopower]

I'm having a similar issue with my van. It runs rough for a minute or two when cold and damp i.e. early morning. It did a similar thing a few years ago. I changed the spark plugs, wires. It was running rough until I also changed the ignition block. After changing the ignition block the issue went away 100% for nearly 4 years.
I'm about to change the sparkies, wires and ignition block but I will ow give the MAF sensor a good cleaning as well.
-Scott