OK, so I'm going to the experts, hoping you guys can help me out with an issue that seems to be stumping everyone I've talked to. I own a 2006 F-150 XLT 4.6L. I started to have issues during ignition about 6 months ago and it has progressively gotten worse. When I COLD start my engine, it will crank but not turn over unless I give it a little bit of gas. If I'm WARM starting my engine it's drastically worse, I almost have to floor the gas pedal to turn over. Things that I'm noticing are the following:

- Starts better/easier the colder it is
- When the engine does turn over, my RPM's bounce around at 1000 until settling somewhere between 500-750 within a minute.
- My engine smells like it's running rich
- When the engine is running I never have issues with stalling out at stop lights or anything
- The warmer my engine is, the harder it is to turn over
- Received a code a few months ago reading "low voltage at RPM under 1000"

Related or unrelated, my truck now wont pass inspection due to my emissions not being ready. I'm getting the following readings from my inspection report:
-MISFIRE: Ready
-CATALYST: Not Ready
-EGR: Ready
-FUEL SYSTEM: Ready
-HEATED O2: Not Ready
-O2 SENSOR: Not Ready
-COMP COMPONENT: Ready
-EVAP SYSTEM: Not Ready

The truck was driven for a half an hour before the inspection and had between 15 and 85% fuel in the tank.

Here is a list of things that have been changed/replaced in the last few months:
- Fuel Pump Control Module
- Fuel Filter
- Battery
- Alternator
- Cleaned Throttle Body
- Cleaned MAF Sensor with CDC Cleaner
- Coil Pack on Cylinder 4 (got a code for misfire on cylinder 4)

Sorry for the lengthy post, but does anyone have any idea what this could be? My next thing I'm thinking of checking is maybe a leaking fuel injector but IDK.

Thanks for any help fellas.

 

I'm leaning towards a leaky injector and possibly clogged cats. How long did you go with that misfire? How old are your plugs?

 

The plugs have about 25,000 mile on them. I went quite a bit with that misfire on cylinder 4. I didn't really notice any missing.

 

Do you think there is any relation with the leaking fuel injectors and my emissions not being ready?

 

What's the longest drive you've taken recently? Hows the engine temp look?

 

misfire will dump raw fuel into the cats... I would have them checked...goes along with want you stated DTC's were.

 

If you had the battery disconnected, you will get this and need to drive it for about 100 miles, that's what happened to me if you are trying to get it inspected and it is failing.