92 explorer 4.0 long crank time

[broncobuckinaround]

Only when the motor is cold it will crank for about 15 secs or longer and stumble a lil. Some times the battery gauge will show low voltage.

I did injector cleaner using b-12 cem tool. Changed plugs to motorcraft copper. Gapped at .53 new wires and o2 sensor. The old o2 wasn't giving any voltage.

Not sure where to start with this one

 

[black_demon69]

Only when the motor is cold it will crank for about 15 secs or longer and stumble a lil. Some times the battery gauge will show low voltage.

I did injector cleaner using b-12 cem tool. Changed plugs to motorcraft copper. Gapped at .53 new wires and o2 sensor. The old o2 wasn't giving any voltage.

Not sure where to start with this one

maybe loosing prime on injectors try Key on engine off wait 3 sec repeat 1 more time then start see if that helps

 

[broncobuckinaround]

Ill try that in the morning since that's when it's the worst. If that helps. That would lean towards a FPR problem. Might be worn out

 

[adsm08]

That would not indicate an FPR problem, it would indicate an anti-drain back valve issue, which means fuel pump.

Or a leaky injector, which means injector.

 

[broncobuckinaround]

Thx adsm08. I found the vacuum line to the FPR wasn't hooked up. And the tps is bad. When I prime the pump a few times I can hear a change in tone that the p u mpg makes.