BlaineElliott

I have a 2007 Ford F150 4.6 V8 XL with roughly 130,000 miles driven. When I first got the vehicle the truck shook sporadically at idle. I figured this was due to misfiring so I got a computer read on the engine error and it stated that 3 out of 8 cylinders were misfiring. I decided to change all the spark plugs out, each spark plug removed was 2X the gap that was meant for the f150. So I placed new plugs in each cylinder with the correct gap size and figured this would clear the code. I disconnected the battery and reconnected it. The truck gained a bit more power from the new spark plugs, but the truck still shook all over the place at idle and even when accelerating. Recently I got the check engine code checked out once again and now instead of it pointing out the misfiring cylinders it is putting out that the MAF sensor and MAP sensor are going bad.

I am just curious as to what might need to be done to regain the truck to it's original condition.

Symptoms:
The truck takes forever to accelerate, perhaps 20-30 seconds to get to 55 mph and when the truck gets to higher gears it starts to jump when trying to shift up, I think this is due to the lack of power behind the engine.

The only time the truck doesn't shake horribly is when I press the gas a slight bit and even when it's not shaking the truck still takes forever to gain speed.

My vehicle won't go over 60 at any given point in time unless going down hill and eventually it'll slow itself down once on flat surface.

What could be wrong? How do I fix this? And what's the least cost effective way of correcting my issues?

Open to all suggestions, thanks everyone in advance for your time.

papa tiger

Get a can of Maf sensor cleaner from parts store. Remove it and spray it with cleaner. Do not touch it. After it is dry reinstal and start truck. Run it for a while. If you have hit on the problem it should run a lot better. A good personal OBI II code reader is a good investment. Not only can you read the codes, you can navigate the pages it offers and discover a lot more about your trucks running condition. Document all you find, and compare it again later. You can find helpful tips at http://www.ask.com/ and http://www.ehow.com/ print out helpful directions for future use. Members will, from time to time, give you other hepful threads to research also. There is a ton of helpful information contained in other forum threads. Run a couple cans of injector cleaner thru the tank and some Isopropyl fuel line dryer/deicer into it to. Sounds like your fuel line filter could need pm service also along with PCV valve and EGR. That's where the reader is invaluable. You can learn so much much quicker and run diagnostics simply.

lariatboy

Replace your FPDM. Takes half an hour, part is $150ish I believe. Should fix your problem.

BlaineElliott

Well the point is I'm not 100% sure on either of those. Cause the first time I got it tested it showed misfiring cylinders, second off it showed that my egr valve was failing/or near failing. Now that I reset the battery it shows the current two problems listed above. I have a few dollars to spare. I just don't want to buy and replace parts that aren't needed to be replaced. Kinda pissing in the air ya know. Another note, I bought a new air filter a month or two ago, and now when I look at it it's dirty as all hell. It looks as though it's been in the truck for a year, yet it's only been a month or two.

sschwemer

I have a 5.4L with 195,000 on it and had 2 issues that caused truck to jump random and bog down trying to get up to speed. Jumping was bad plugs and three coils misfiring random. Changed all and issue went away. For my bogging down issue it was the throttle body full of crap. While T.B. can be cleaned mine was so trashed I put on a new one and cleaned MAS. All issues gone now and runs like new. Only thing I have not checked is the EGR to see if looks ok. With everything people say on this site your issues most likely is one or a couple of above. Hard to say these days with so many parts.

sschwemer

I would sick to fixing the codes (misfire-plugs and coils replace), erg (clean or replace). Best place to start if the comp. is telling you this.

2002VertGt

This sounds exactly and I mean exactly like my 04 5. 4......it has no power, shakes spits and stutters if you give it a lot if gas, it is throwing misfire codes on 1 2 &3, lean on bank 2.....I would check the maf and tb, if that's not it then it may be what they Are telling me (2 mechs with one being a ford service rep) that it is the timing off. Hope you find your solution soon

60DRB

The first and cheapest possible solutions are as previously stated. Clean the MAF sensor and throttle body with appropriate cleaners (and a new air cleaner from what you describe). That's cheap and will at least give you a good starting point for trouble shooting. After that, see if the EGR fault is still listed... other things that might be at fault include COPs and associated pieces (check connections, etc), MAYbe the FPDM, ...

2002VertGt

The fact that he is misfiring on almost half of all cylinders and it has no power I really believe is going to be timing. I'm dealing with the same thing. I have replaced spark plugs, cops, fpdm, fuel filter, cleaned maf and tb and its still acting exactly like he described. I will be resetting my time by the end of the month hopefully and I'll be able to tell you for sure if that is the culprit or not.

OP, change the air filter and clean the maf and tb. Your looking at 12$ for the cleaners and a air filter (not sure about the price on that maybe 15-20). If it doesn't work I think you are in the same boat as me. If you want to replace the fpdm get it from rockauto.com. I'll let you know when I reset my time if it fixes mine.

Mr.Bones

Are the miss fires only on one side of the enigne? Have a back presure test done. You may have a cloged cat.