Engine has low rpm miss, skip or shudder

[mjm97stroker]

2003 7.3 L has a miss, skip or shudder from about 1200 rpms to 1500 rpms. To make the shutter go away I just step on the throttle a little more and the skip goes away. When I mash the skinny pedal the truck takes off without a problem. The engine starts up quicly even in the cold weather. The truck idles smoothly and makes plenty of power up top and generally runs well except for this.

The skip is more noticible with the higher HP settings on my TW Chip (extreme). My MODS are in my signature. I don't notice any miss at highway speeds (55mph and up). There is no SES light. I checked the oil rails to make sure they were full of oil and I drove the truck with the ICP sensor disconnected and it didn't make a difference. I'm hearing a louder than normal clackity, clack from the drivers side valve cover. I'm thinking maybe an injector is going bad. Any help would be apreciated.

[Codum]

Found this old post and curious if the problem was ever solved. Mine is doing the same thing and can't figure out what the problem is. I have had a low torque issue with this shudder for over a year/ 45,000 miles. Any ideas much appreciated.

[greasyF250]

My problem is a rough idle then smooths out after 1500 RPMS. I'm making a wiring harness that I can put into the VC connector so I can shut off each injector . 1 at a time to try to isolate which one is bad . I know its on the dr side at least.

[mjm97stroker]

It was a bad injector. I ran test after test on my A/E software for a year before it finally gave me a couple of failed injectors. I swapped injectors around to figure out which was the problem. Since I had 125K on it and I wanted more power I ended up replacing them all with Rosewood Hybrid injectors and new tuning. problem was solved.

[Codum]

Thanks for the quick response! I am thinking injectors also, but have no sign of that being the exact problem. All buzz and contrubution test at ford dealer was good. I have a scan gauge and no cel, good ipr#'s and icp pressures. Like you good cold starts, just like when new, no smoke except on a hard acceleration. Thinking about full force stage one's and PHP 6 position tune. Thanks for the help!

[mjm97stroker]

You will not be unhappy with that choice. I figured if I was going to spend the $$ on new injectors I might as well go bigger. It is real nice the engine pulls all the way through the rpm range intead of running out of steam at the big end. Just watch your EGT gauge. Plenty of Towing power. I pull 10-12K on a pretty regular basis. 14mpg towing, 16-17 around town summer, 15-16 mpg winter, about 20 mpg on a trip as long as I keep it around 70 ish on the interstates.

You might want to change your injector cups when you pull the injectors. Its relatively simple since you will have everything apart anyway.

Good luck.

[Codum]

Thanks, for the advise on the cups.