I had a 7.3 Powerstroke before my current Cummins, and I had a spare CPS in the glovebox at all times, change it and see if it cures your problem

 

What you are describing sounds like to me a deffinite miss, a cps will absolutely, positively not cause this. A cps failure will cause a stalling and a no start condition on that engine, if you had a cps code on your scanner then I would lean toward it being a culprit only because it has proven to be a reliable trouble code, and that is only if the engine is stalling or no starting.

A cylinder contribution test, or an injector buzz test can be misleading, and most aftermarket scanners cannot perform the required tests to isolate what injector is having an impending failure. My best guess would be a #8 injector with an impending failure, it is a long lead injector because it is the last one to get fuel, and is the one that is most prone too failure.

A Ford scanner may be your best option.

Best of luck for a speedy resolution.

 

Did anyone do the simple things first like fuel restriction and air in the fuel checks ?

 

How about the High Pressure Oil Pump pressures? I am guessing but no one else mentioned it.

 

Not true. When a CPS begins to the failure oftentimes begins intermitentently. The no start condition is when tthe CPS is 100% failed. Stalling and missing is the CPS beginning to fail. When my CPS started to go failed (at approx 110K miles on the truck), my truck had a 'miss'. Replaced the CPS & the 'miss' went away.

 

A failing cps will not cause a high rpm miss. It could be low fuel pressure which could cause an injector to miss at higher rpm, or poor oil condition, which has been an underlying cause of different drivability concerns. Mark, I agree with you on the point of a cps being problematic for the 7.3, but any rough running or "miss" condition associated with a cps failure usually occurs at engine idle or low load, low rpm operation. It looks like they are spending a LOT of money throwing parts at this engine hoping to find the fix. That is why I recommended the Ford scanner, more engine specific tests than what is available aftermarket.

 

I've had CPS troubles on a 99 PSD before as well, erratic miss, lack of power stalling just off idle etc. There were no codes set. CPS completely fixed the condition.

 

We ended up pulling all of the injectors and sent them to M&M for testing and rebuild. Our mechanic is betting on a bad #8; we shall see. I still think we should have swapped the CPS, cheap and easy idea.

 

That was the only way my co-worker found the problem on his '99...

K.

 

Are you running Ford Diesel Oil??????? I know that they have had some issues where the truck would not get the proper fuel pressure because of foaming oil???????????

 

Cps should throw a code, but it doesn't always happen. I had 2 go bad on 2 different trucks and niether gave a code. Others I know have seen the code pop up on their trucks before the CPS totally crapped out.

 

Exactly, I had one that would only act up when it rained hard enough to get it wet, then it progressively got worse. The CPS is kinda hit or miss, some just die with no prior indication of any problem, others slowly wear out and cause the same problems the original poster has.

 

I know what it needs. A good insurance policy, and a match.