1999, F-150, 4x4, 110k miles.

History: About a year ago, we replaced the coil packs, wires, and spark plugs due to codes relating to misfires. The codes cleared up for a while but came back intermittently after a few months.

Currently getting a code for #3, which was one that we were getting before.

Now: My son was driving the truck to college (700 total miles of which 450 on the 2nd day) in 2WD. About 30 miles away, he went to pass someone and when it downshifted it would not shift back to overdrive until he let off the gas. We passed several people that day.

It does this at the lower speeds also and I hear some back firing now.

Is the shifting issue a completely different problem from the cylinder 3 code? ERG ports need cleaning? Transmission solenoid bad? Something else?

I wanted to get some advice before Friday. I'm going to my son's college and plan to fix it when I'm there. So I would like to have a plan before leaving so I can bring all the tools I will need. Or if it is even something I can do.

Thanks,
Brian

 

Code is P0303

 

Is it low on power (something having to do with your code)? Sometimes issues with power can cause erratic shift points.

 

If it has coil pac...multiple cylinders per coil pac....Hmmmm gotta wonder if that engine has been replaced with a slightly older unit? more 97 vintage

If it has individual coils per cylinder AKA Coil On Plug (COP) or the spark plug it self.

I'd pull the #3 COP or plug wire and note inside the spark plug well if there is moisture or Oil ....or something around the plug...clean it out as best you can. The remove the plug...

install new spark plug in ole #3...torque to 28ftlbs...

take special care as how the connection to the COP or coil pac making sure that it is good.

 

What motor size do you have for this year? It makes a difference in coils used.
Since you mentioned coils and wires I will assume it is a 4.6L..
Next do not keep running with a cylinder out.
A hard code of 303 is next to last one on passenger side.
Inspect the boot, the wire and the terminal on the coil pack closely.
There is a reason it has failed.
It may be related because more throttle has to be applied to keep road speed up preventing OD upshift.
Other wise there could be an issue with the TPS sensor that also greatly affect shifting points vs load.
Good luck.

 

Low Power YES. Engine revs high but doesn't seem to be able to pick up speed.

4.6L Coil Packs, Wires, and Spark Plugs have been replaced within the last year. I'm not sure what it is called, but the spark plug wires have something on them where it connects to the plug. We were getting a code 303 before replacing. It was fine with the new parts for about a month and then started coming back periodically. Now it is back fully.

Fire Wall
4 8
3 7
2 6
1 5
Radiator

 

Just because parts are new doesn't mean they're good. Check to make sure the coil pack isn't burned looking (might even be able to smell it), and that the wire isn't loose. You'll probably need to replace the coil pack. The next thing is to figure out what's making the same coil pack go bad.

 

Should I swap the packs and check it?

 

I've done some more research.
I'm going to get an HEI Ignition Tester to verify the coil pack.

Does that make sense?

 

Sure. You can also swap the pack out as you said.

 

I will be working on this all day and checking this thread.

Son says check engine light has not been coming on (P0303) I went ahead and checked it with an Ignition Spark Tester and it was good. So not the Coil Pack. I'm going to consider P0303 case closed.

Still have the high fan/rpms and have to let off the gas for the transmission to shift. I also have low power.

 

One additional note. This started all at once at the end of a long trip. (high fan/rpms and letting off gas to shift)

 

I don't think the fan clutch is disengaging, so I'm replacing that. This could cause the acceleration and power problems. Which would mean I was looking at two different unrelated failures. I'll post results and I'm still open for suggestions.

 

Not completely sure what to tell you as of now. Keep posting what you're getting done.

 

Before replacing the fan clutch make sure it's faulty.
With engine fully heated hook up a timing light to any cylinder and aim it at the fan blades.
Wait several minutes and watch for the strobe effect on the blades to change when the thermostat opens and closes.
If it does not change, the clutch is faulty or the cooling system thermostat is faulty..
Good luck.