99 F250 powerstroke miss

[bishop021]

I have a 99 7.3 with a really bad miss at start up and it continues to miss like crazy if you drive it and has no power, then all of the sudden it will go away in stages. Its like there's 3 boosts of power then it runs fine... Truck has 245,000 miles. I have a ts 6 position chip, intake, and 5 inch exhaust. I've hooked the newest updated snap-on scanner up to it and there's no codes. Any ideas please?

[kemp2011]

I had a 2001 f350 in my shop with what sounds like the same problem. It was hard to start and when it did, it ran real sluggish and skipped but no codes. I have seen this on a couple of trucks. It's probably going to be injectors. Pull the valve covers so you can see the injectors. On the top left corner of each injector there is an allen head bolt that attaches the oil spill port. Start the truck and seeing how much oil is coming from each one. A bad injector can be identified by observing the flow of oil out of the spill ports. If no oil flow, the injector is not opening (the hydraulic part of the injector is bad). If oil flows constantly, the injector is stuck open. With this method, I found 7 bad injectors. All injectors past the KOEO injector buzz test. I hope this helps.

[bishop021]

Thank you. I'm going to run the buzz test in the morning and if no codes I'll tear it down and do what you said. Thanks again...

[kemp2011]

Let me know how it goes.

[bishop021]

Ran the buzz test on the injectors and some weren't as loud as the others. I tore it down and watched the oil ports and all but one were working properly and 2 not oil at all... Any suggestions on where to purchas any?

[jc82chevyman]

Well it depends on what you want, there are several vendors who sell reliable rebuilt units as well as new ones if it was me I would probably go with full force diesel

[kemp2011]

When you say "working properly", how much oil was coming from the ports? If it looks to be close to a steady stream of oil, then those aren't working correctly either. On a good injector, there should be only a small amount of oil coming from the ports. You really have to pay close attention to it.
As far as injectors go, if you are going to buy online, I would just do a little price shopping. I would go ahead and replace all eight. With the miles you have on the truck, chances are if you swap just the known bad ones, you will be replacing others soon. If you aren't going to do any other mods than chip, intake, and exhaust, I would just get a set of rebuilts. You want to pay attention to the valve cover gaskets before you reinstall them because of the wiring harness.

[bishop021]

It wasn't a steady stream coming out, more like pulsating. Only 2 of them were putting out a decent amount. 4 were just barely doing anything, and 2 didn't put any out.

[kemp2011]

It sounds to me like the 4 that are just barely doing anything are good. The 2 that are putting out a decent amount are stuck open and the other 2 won't open at all. I'm glad you were able to find the problem.

[bishop021]

Got the new set in today and fired it up and it runs great!! Thanks for the help!