2001 F150 V6 p0171,p0174,p0303

My truck started to shudder pretty badly while I was at lower RPMs particulary those associated with gears 3 and 4 (Manual Trans). Truck threw these codes and did a tune up except for the ignition coil. Cleaned my throtle. Cleaned my air temp sens. New Fuel filter. Checked for leaking vac hoses- when I did this I found on the passenger side Valve cover there where three hoses that come together and then connect into the cover...that connector was off, I reinstalled it, loose but on...still codes and still engine shudder. WTF? when the truck gets to cruising speed it gets better unless i am on the freeway then the check engine light flashes but the engine isnt shuddering.

Any Ideas?

These are bad about the PCV elbow becoming soft and causing a vacuum leak so check all those real good. You say is sputters at low rpm when cruising. How does it idle is it smooth or rough? If you already tuned it up and still sputters then try to remove the vacuum line from the egr valve and drive it again. If the sputtering is gone then the EGR passages are clogged. Let me know and Ill tell you how to fix.

Have seen this several times,the pcv valve 90 degree hose on the back of the intake will dry rot and cause p0171&00174 just like asecmt said
Here is the link for p0303...http://www.obd-codes.com/p0303

Thanks for the advice.

I checked all of the vac lines and they all have good vacuum. The 90 underneath my throtle body has been replaced by a straight and a hose clamp. so it seems that that is not the issue. I double checked all of my hoses and they dont have any leak sound when the engine is running.

While I was in the middle of this i noticed that my coil pack is cracked and one of the bolt tabs is busted off. Im wondering if there is an issue with the #3 in that mechanism. It looks like it is the original coil pack so I will replace that this afternoon.

At idle the truck is great. Now since i messed around with the coil pack last night the problem has gotten worse. Now In every gear when i place a demand on the engine it shudders and flashes the CES. But that wouldnt cause the P0171 P0174 codes tho? there is a leak somewhere. Im just not able to find it?

Well if when you messed with the coil pack and it got worse then thats very possible the problem with the misfire. If it idles smooth then if there is a vacuum leak is a very small one, you could have a problem with the maf being dirty have you tried to clean it? Are you familier where the elements are in the maf to clean? After you clean it be sure to remove both battery cables then touch them together for about 20sec or so clear all the memory in the pcm, unless you have a scan tool that can erase the KAM in the pcm.

The #3 cylinder coil is the 3rd one back on the passenger side of engine if that is the cracked one.
And the 90 degree rubber elbow isn't under the intake it is on the rear of the throttle housing,the pcv valve is on the center of the passenger side valve cover,just follow the plastic line on it around to the back of the throttle housing, that is the 90 rubber elbow in question,also a lot of times you can't hear the vaccum leak at that elbow.

PROBLEM SOLVED

I found a crack on my ignition coil on the #3 Cylinder plug connector. So I replaced that and the shudder went away instantly along with the P0303.

Also I started my engine and removed my PCV and let the vacuum suck about 1 cup of Sea Foam into the engine. When the engine started to run rough I turned it off and did the following.
I bought some electrical cleaning solution (quick dry) and sprayed the s**t out of my MAF and reattached everything.

When everything was put back together i started my truck....do this outside....it coughed and sputtered and shot black nasty out the tailpipe. I gassed it a little and rev'd the engine until the exhaust ran clean.

Cleared my codes
Drove it for about 15 min.
No codes no shudder.

Thanks for all the advice guys.