Hi guys. I've been searching and searching with no real help. Several folks that had similar concerns but nothing that I've been able to pin down the same as mine...

Back story: Bought the truck used at auction. Pretty clean 2007 5.4 lariat. Looks to have been pretty well maintained overall. Got it trailered home and starting driving it back in July. Overall it ran pretty good. Had some definite timing chain rattle going on. The biggest issue though is that once every couple of days when you go to accelerate from a stop or almost stop the truck would bog hard and backfire through the intake. Let out of the throttle pedal and go again and all is fine. Drove it that way for a while until I got time to look at a few things. Started checking parts and you could tell that the MAF, TPS, MAP sensors are all new. had two new coils etc. I pulled and replaced all plugs and coils anyways just to know where I'm starting. Kept driving it with issue showing up randomly. Kept thinking that it was somehow due to the VCT really going out of range. Finally pulled the timing apart a couple weeks ago and found two broken guides and a leaking tensioner. Replaced all parts with new and installed a high pressure pump. While in there I locked out the VCT sprockets and tuned them out. Truck drove flawless for a few days and then started doing the same thing again... Once warm engine does idle a little rough but not a dead miss. Only codes set are rich both banks. I've run injector flow tests multiple times always with good results... Fuel pressure remains good and steady even when condition is happening. Don't see any data that seems out of place. What am I missing?!

 

I have an 07 Expedition 5.4 3v. I have a dead Miss at #1 and that backfire through the intake speraticly. Sounds like a "peck". I changed everything out, plugs, coils, both cam sensors, no vacuum leaks, switched the injectors into different holes. (Its most defiantly not an exhaust tick or torque converter/tranny problem) and I have the right valve cover off as we speak, everything looks okay. Only code I have is the #1 misfire (P0351 I think). I'll keep you posted and you do the same.

 

Both of you might want to check compression.

 

Have you re-mapped it since locking out the phasers?

 

He did say that he tuned them out, so probably?

 

 

I checked the compression on mine and its 180ish on all 8 holes so I'm gonna check the wiring and fuel pressure next. Thanks for the info.

 

On torque pro its under test results . It tells by cyl the raw computer counts building towards a misfire cel it also gives you the count it must reach to set same . The threshold is high .
There is a exhaust back fire or a intake back fire . Yes compression test is a must . Look at st and lt fuel trims . Check out your o2 readings . Can you determine your cat condition , If your o2 sensors not working its not going to go to closed loop . Rich condition is going to burn out cats .
Misfires can cause a lot of this . Not to mention timing problems . Valve problems /lashs /valve sticking ?Worn rollers . Most of all get oil system clean ,your heads need clean oil even if you locked phasers which I am not a fan of .
Just how good a tune was this to get rid of phaser action . I know livernois is around $700.
Let us know how your testing is going . Me I would attack the plugs/boots in hosp clean way , if plugs aren't right you will be chasing your tail . Clean all cop connections . Torque plugs in 25 to 28 foot pounds not by feel . Be very very dilgent doing plugs right . It is very easy to screw up , they will be good for only 60k . Be on the lookout for leaking injector ,rails pulled on dry newspaper key on none should leak .If not plugs/boots ,how sure are you of timing .

 

First, thanks for all the great info. Ive heard torque pro is pretty awesome. Im gonna be tight on time working on mine between work and 4 kids. I went ahead and had an MMA natch with the right side valve cover and pulled it just to ease my mind. Everything seems to look okay, I think I'm gonna bump it over and watch that #1 up close before I put it back down. I am gonna go ahead and pull the injectors and check them out while I have a bunch of crap off there and cut that T out of the heater hose even though its not leaking. I think its been replaced before. The phasers and timing junk have been changed out about 80,000 ago (its at 220k now) and I keep the plugs changed out in both it and my 05 GT. Im only using my Rev-X tuner for scans and I dont know its capability as far as "scanning" it's pretty much just a code reader I suppose. My friend that helps me on my cars just mentioned something today that hit me hard. He said the clip was broken on one of the passenger side COPS that he didn't think was a big deal. If it turns out its on #1, I may have the miss figured out. Ill keep you posted as soon as I can get back under the hood. Thanks again.... A bunch!

 

It is very powerful . i wish I knew more .Its not one those $3000 professional jobs that can command solenoids etc . Yes your connectors must lock on to cops and injectors ,you can solder in new ones use heat shrink. Cop connections are bad about corrosion clean them and high volts tab also .. I am going to have to make a cut and paste file because I forget to tell some of this each time . Those plastic connectors just fall apart with the heat ,get the ones with a pigtail on them . Some guys temp use tie wraps until they get shipment. The plug job really needs a sticky as there is so much to it .
Yes put some rags down and see that oiling taking place while running . You can put some tupperware over phaser to catch oil but don't let rags get caught ,I would do this with a cold engine .It does throw a lot of oil .Have someone to start and stop it for you ,spend your time observing .