So I'm new to this, but heard that there a lot of great people on here that have tons of knowledge. So here goes. I have a 03 7.3 f250. I'm have trouble with the first initial 20 minutes of the truck starting. It starts fine but if I throw it drive and start to go it's shakes bad runs horrible and will sometimes stall out. If I let it idle for 15 to 20 minutes first and then drive it it runs perfect. I have replace the fuel filter, and air filter. The truck has roughly 125000 miles on it. Any help would be greatly appreciated. Thanks in advance!

 

You are definitely in the right place. There are a ton of knowledgeable and helpful people in here.

You didn't say anything about any modifications, so your truck is 100% completely stock, right?

Do you have a way of pulling codes? Is the SES light on?

 

So yes completely Stock. I haven't done anything to it yet. I do not have any way to pull codes. What's crazy is , is that after 20 minutes or so if I told you that something is wrong with the truck you would never believe me.

 

What kind of oil do you have in it (brand and viscosity)? When was the last time it was changed?

 

Rotella t 15w 40. I just hit 3000 since last oil change.

 

Rotella t 15w 40. I just hit 3000 since last oil change.

 

Do you have a glow plug relay or a glow plug control module? GPCM was mostly California trucks.

 

This may sound stupid but how do I find out.

 

Under the hood, passenger side top of motor by the firewall. There are two round relays sitting right on top of the motor, one forward and one aft. One will be a little lower in elevation than the other. Round, about the diameter of a small oil filter with 2 big wires and 2 small wires connected to the top. If you have this configuration, one of those relays is the glow plug relay. If you only have one relay there, you have a GPCM.

 

There are no stupid questions, only stupid answers.

 

Reason I ask - The glow plugs in cold weather will cycle on and off when the motor is cold in certain conditions to keep the combustion chamber temperature adequate. It is a long shot, but your relay might be shot. Park your truck in a dark spot pointing towards a light colored wall. Start the truck with the motor cold with the headlights on. Focus on the amount of light the headlights emit. You should notice the headlights perk up about 1.5 - 2 minutes into the warmup idle. Don't get ADD and look away or you will miss it.

 

Or if you have a volt meter...

 

Are these the relays ?

 

No they're not. They are on top of the motor, not off to the side.

Glow plugs is a good thought. I have a voltmeter that plugs into the 12V outlet and it's very clear when the plugs are on and off if you pay attention to it. It's much easier to see than when the headlights perk up. They do, but it's very easy to miss.

 

The relays look like this one...