I'm having an intermittant starting problem on my 90 302 F150 MT. It usually occurs after I've been driving. By this I mean after I've gone to the walmart, etc, come back out, and am ready to go home. The engine will rotate very, very slowly and eventually come to life. When this happens, while cranking the volt meter can drop below 8, and some of the time is between 8-10 when cranking. Normal starts are above 10v. Heres what I know:

Battery:
1 year old Interstate, charged
clean terminals
Tests good
Standard F150 size
I put a charger on it after this happened once when it was cold and it took some juice

Battery cables:
Newer, checked good (not verified)

Connections, ground:
Checked good (not verified)

Starter:
New. Replaced because this sounded like the starter had a "bad spot". Old starter tested good at bench.
Checked for oil on starter. Negative.

Alternator:
1 Year old
over 14 volts on voltmeter when running
normals starts are above 10 volts.


This has happened when it is winter or summer. Once this winter it happened and I had someone jump me...started right up.
Since it only happens after I've been driving, maybe the starter gets hot??

I still suspect the battery, even though it tests good. I drive far enough the battery should be charged by the alternator.

Suggestions?

 

If nothing else this reply will bump you to the top of the list. Looks like you have covered just about everything, however, the fact that when you got a jump it started right up would make me think that your battery is suspect. with the battery being not long new it would be a tough call to buy new so soon.