2008 Ford F-250 superduty bogging down under load and random times

[rk1407]

I just picked this truck up at an auction so I don't have much history on it except it has 65,000 miles on it. It came out of a State carpool and the only thing the mechanic said to me when I picked it up was it has had regular oil changes with synthetic. It is equipped with a 5.4 V8 gas engine.

So I got I towed it home and the tank was so dry it wouldn't start. Put some gas in and it started right up. Drove it up and down the road a few times purred like a kitten and very responsive throttle.

Next day, I went further down the road onto the highway and hit the gas pretty hard and it completely bogged down and just started sputtering and jerking. No check engine light and no codes in the system. It never died but got close a few times when I pulled into a gas station. If it felt like it was about to die I just tapped the gas and it helped. The last mile to my house was a pretty long uphill stretch and the truck was just struggling but never died or threw a code and still no check engine light. Any thoughts on what this could be?

Thanks in advance, I appreciate any guidance on this.

 

[Rand]

2008? sounds like you could start with the basic tuneup type stuff.. then go advanced with cheap odb scanner gear.

 

[D60]

Sounds like FPDM. Look for corrosion

 

[clinebarger]

'08 should have the updated 12mm spark plugs, You will need a 9/16" spark plug socket.
If it does have the early 16mm plugs (5/8" hex)....Removing them is a top priority!! Get the engine nice & hot before attempting removal.

At 65,000....You shouldn't have any ignition related problems, But age & environmental usage can play a part.

If it's lean popping through the intake....Check/Monitor the fuel pressure via the fuel pressure PID in scan data.

3V powered Super Duty's are known to melt down catalytic converters from being pushed to long with misfires.

 

[mattd]

Replace the spark plugs. Classic symptoms for this truck.

If you want any, hope of getting them out in one piece do it with the engine hot

 

[ripcord]

I'd do all the maintenance things first. The fuel filter is cheap and easy.

Spark plugs may or may not be a headache as 2008 was the year they switched from a two piece spark plug that is prone to breaking off in the head to a one piece design that fixed the problem. If the stock coil on plug boots are black you have the two piece type heads. If the boots are brown, you have the later updated version.

The correct plugs for the early version with black boots are Motorcraft SP546 and the later plugs with brown boots is SP509.

 

[meep]

High voltage side of things is suspect, fuel delivery would be next.

 

[The_Eric]

I recommend that when you're in there looking at/changing plugs, to pull the boots and springs and look at the little spades on the bottom of the coils. I've noticed that many of these will corrode which can lead to misfires.

 

[ripcord]

I recommend that when you're in there looking at/changing plugs, to pull the boots and springs and look at the little spades on the bottom of the coils. I've noticed that many of these will corrode which can lead to misfires.

I have always replaced the boots when I do the spark plugs on a Mod motor. They're often really dirty or oily. Don't forget the dielectric grease.

 

[97prizm]

I just picked this truck up at an auction so I don't have much history on it except it has 65,000 miles on it. It came out of a State carpool and the only thing the mechanic said to me when I picked it up was it has had regular oil changes with synthetic. It is equipped with a 5.4 V8 gas engine.

So I got I towed it home and the tank was so dry it wouldn't start. Put some gas in and it started right up. Drove it up and down the road a few times purred like a kitten and very responsive throttle.

Next day, I went further down the road onto the highway and hit the gas pretty hard and it completely bogged down and just started sputtering and jerking. No check engine light and no codes in the system. It never died but got close a few times when I pulled into a gas station. If it felt like it was about to die I just tapped the gas and it helped. The last mile to my house was a pretty long uphill stretch and the truck was just struggling but never died or threw a code and still no check engine light. Any thoughts on what this could be?

Thanks in advance, I appreciate any guidance on this.

Fuel filter. Under light loads maybe it has enough fuel flow under heavy loads it can't flow enough fuel.

 

[D60]

If he's getting misfires he'll almost surely get codes and CEL/flashing CEL.

Fuel is the one thing that can drastically affect performance and rarely set a code, even though this probably has/should have a FRP PID.

I'm not saying it's 100% fuel, but checking spark plugs wouldn't be the first thing I'd chase. However, pending codes and misfire counters should be looked at (fast and free)

That said, I think OP entered a wormhole and we'll never know.

 

[mattd]

This generation of fords is terrible for setting misfires. The counts must be extremely high. Your best bet is mode 6 data with no codes