7.3 hard starting, flat spots at high speed/rpm
 

I have a 2001 F350 Dually 7.3 w/260K miles. Hard starting, it has to be plugged in all the time. Occasionally/most of the time, blows white smoke at 50 to 60 mph or at high rpm. Replaced TPS and now runs totally different on starting, still hard to start but better throttle response on starting. Once started, I have to pedal it to keep it running, which seems to have little response as it would as if it was a direct throttle linkage attached to a carburetor...follow me? After a while, it will idle by itself. However, it still has flat spots when out of idle and at high rpm. Has gotten to the point that I can't trust to drive it.

Welcome to FTE! I have several questions.

How long does the WTS (wait to start) light stay on when you turn the key?

What kind of oil are you using?

Have you checked the oil?

Have you checked the oil level in the HPOP reservoir? (High Pressure Oil Pump)

Do you have a way to monitor sensors on the motor? Read codes?

Have you looked at the fuel filter or changed it lately? What color was it?

How old are the injectors? Original?


With no other information, I'm guessing o-rings or IPR. Faulty glow plug relay is also a possibility as for the starting issue.

I'll see if I can get this moves to the 99-03 psd forum.

Thread moved... Welcome to FTE! :-X22

What is the weather like? These trucks need the GP to work if the temp is in the low 50 or colder. You may have more than one issue. If you are in the 70F-80F the GP do not activate but the WTS light will.

I would take the oil cap and flip it up-side down on the filler neck. If the cap hovers off, we have more troubleshooting to do. If the cap bounces off the hood and ricochets into parts unknown... not so much with the troubleshooting thing. I can promise when the next step is done, you will have found your wayward oil cap.