Alright fellas, I apologize for this may be a long post but please read. Any opinions/advice are much appreciated at this point. I have a 2010 F250, 78000 miles, with the V10 obviously and I just cannot get er to run right. At first It had a miss and was just running like crap at an idle but would seem to clear up significantly when crusing over 2000 rpm. It would start pretty hard and You could hear a bad air pressure leak whether it be vacuum or pushing coming from near the throttle boddy, almost possibly inside the throttle body, and an exhaust leak on the drivers side manifold. I pulled a few plugs and they were wore out to the point that the gap was over .090. So using the proper methods I put all new motorcraft plugs gapped at .040 in and new boots. Cleaned the connections on all cops, cop plugs and fuel injector plugs. Cleaned the intake tube up good and the MAF. I also pulled the throttle body and cleaned it up. Changed out the drivers manifold gasket and changed the fuel filter which turned out to be pretty clogged. After 2 days of work I hooked the battery back up and crossed my fingers. It fired right up the first time but was still running a little rough. The miss seems to be gone but it still shimmys at an idle and you can still hear that air pressure from around the throttle body. I have sprayed starting fluid on every vacuum line I can and around the intake, no change what so ever. Oh and the exhaust leak is taken care of. It is definitely running better but by no means right. I forgot to mention that when first fired up the brakes are real stiff like theres no vacuum to the booster but after its been given some gas the brakes go back to normal even after stopping. I go to pull it out of the shop to drive it and it seemed to shift into reverse allot harder than usual. I ease down the road and its still a little choppy, then I give it to her and it smooths out a little bit and runs ok. Something new is that when cruising around 1500 rpm the engine give off one heck of a shimmy, but drop the throttle or give it more throttle it disappears. I drove it about 15 miles and the CEL came on. Stopped at auto zone and had the code pulled, turned out to be bank 2 running lean. Drove a little more then shut her down for a while and cleared the codes. Drove it again for about 15 miles before the CEL came back on. Pulling up the stop light it starts to run pretty rough but kick it into neutral it cleans up quite a bit. It still starts kinda hard, seems harder right after it has been running. Im at a loss here guys, I feel like its definitely vacuum related or is causing vacuum issues but I cant figure it out and I need some input big time, I really need to get her up to par. Any input will be much appreciated and thanks for taking time to read. I also grabbed a video of it idling to hopefully help and put it on youtube, here is the link...2010 f250 idle - YouTube

 

Plug off your vacuum line to the power brake booster and see if it clears up, if not plug off the line going to the vacuum canister and see if that helps.

Denny

 

Something is definitely wrong with the brake booster or the one-way vacuum valve that the hose connects to on the booster itself. The peddle shouldn't be hard after sitting overnight. With both the hard pedal AND the idling/running issues, it sounds like the brake booster is leaking internally.

Like Denny said, plug off the line to the brake booster and take it for a drive - be careful though, you won't have power brakes

 

Regardless of the above great suggestions, I would also run a couple bottles of Seafoam through your injectors just in case. It does sound like an air leak somewhere. Keep us posted.

Pap

 

Allright men. Thanks. I'll go and try these suggestions now and let you know.

 

I unplugged thew brake booster before the one way check valve and plugged the line good, no change. Unplugged the line that feeds the canister and plugged, no change. Checked my plugged lines with starting fluid and confirmed they were plugged good. What I did notice is that when there is an open vacuum line it seems to run slightly better and then when I plug the vacuum leak it goes right back to running like sh**. Whats next?

 

You have to figure out why it's lean in bank 2 - you might have a plugged injector - lot of work without any guarantee of success - you did the plugs? Were any really white compared to the rest?

 

Well I just rechecked all the plugs, when I pulled them I numbered them so it was a breeze knowing which cylinder the plug came from.The only 2 plugs that really seem whiter than the rest are #5 and #10. It wasnt spitting out any codes for running lean before the fuel filter, plug, and manifold gasket change. I have also ran a half tank premium with lucas injectore cleaner through her and currently have a tank of premium with sea foam.

 

I just pulled the the oil cap off and there is a lot of vacuum pressure (pulling air from outside down into the valve cover) Is that right? Correct me if im wrong but there shouldnt be vacuum at the valve cover, atleast not that much. Replaced oilcap and pulled the hose that runs to the intake tube...same thing. Check the drivers sider and there is hardly any vacuum on that side. Stuck valve or what? Im here to tell ya gents, this ones got me. HELP!!! Thanks guys

 

Is there a rip anywhere in your air intake boots?

 

Or the hose that goes from the left valve cover to the intake boot. I really think you have a air leak or vacuum leak somewhere.

Denny

 

Well Im feeling and really hoping that its just a vacuum leak but I cant fine one with the starting fluid. I just checked the intake boots and the hose that leads to it from the valve cover. Both are in great shape.

 

Any other advice to give guys? Would really appreciate it. Any one think it could be a blown intake gasket?

 

check the PCV valve

 

I would not use starting fluid to check for a vacuum leak because of the way it vaporizes and burns I would use something like carb cleaner or anything that doesn't burn very well. It's easier to pick up a stumble in the motor than a increase in speed caused by the starting fluid.

Denny