Forrest150

I have a 2005 5.4 Triton that has been having some serious problems . My truck has been in the shop for 2 weeks and has seen 3 mechanics with no luck. Let me try to make this long story short. About 3-4 weeks ago at a red light my truck stalled out and would crank up again, i then reset my Edge and it everything was fine. Since then i got rid of my edge to get a new programmer ( which i havnt got yet ). Between this time the truck has gotten much worse. Not about 30% of the time it wont crank up the other 70% of the time it will crank up but will choke its self out very shortly after even in idle. It will throw the wrench light and the engine light. My normal tech told me it might need to be reflashed. I took it to ford to get it flashed and they did but it didnt fix the problem one bit. Every computer its plugged up to says it has bad throttle body. I have replaced the throttle body and mass air flow sensor ( both did nothing and would still throw the same codes ). I took it to a really reputable ford mechanic in town and he works on 5.4s all the time and told me it might be the PCM, he just did one 2 weeks ago. He gets the truck and says it doesnt present the same, he claims there is no real way to prove if the pcm is bad but my wiring harness is good and the throttle body and intake is good. it is the only we are left to believe? Any help or ideas??????? thanks!

melrose99

Bad vacuum..????

Forrest150

I dont think so because the rpms go really high and really low until it chokes out and if it was a bad vacuum it wouldnt go high right? And a ford computer would tell them vacuum?

Especial86

iTrader: (1)

Likely an FPDM

Could also be the TPS sensor if you haven't replaced it yet.

papa tiger

X2 on above also: The vacuum leak will create the revs and then kill 4 sure. Search hard for the leak. It may be in the intake before the throttle body.

Forrest150

Already did the fuel pump and FPDM about 6 months ago. I just think if its anything other than PCM we would be getting the code for it right? Idk about the TPS

papa tiger

Run a HEC test to see if the ECU is talking properly with the Cluster. Check to make sure your Maf and supporting hose are sealed. They can make a fool of you. If you haven't changed your spark plugs recently do so. I understand it isn't clanking like a diesel ? The ECU would probably code if it had a fault. The vacuum leak is probable. They can be so tiny and yet so bad on the motor and hard to find. A split hose or cracked and off.

WadeFX41970

My friend, I have a 2006 F150 FX4, with the 5.4, 3 valve in it, 129k on it, I bought it from a guy back in May, knew nothing about it other than the older guy that was selling said something was wrong with the Motor as he put it. I ask did it crank and he said yes he had driven it to Moultrie, Ga. The day before, so I'm thinking, Phasers..So I bought the truck, it's a good looking truck, in great shape, underside is rust free, when it was dropped off at my home I drive it and found that it did need a timing job, but it was also really slow to accelerate, shifted badly, fuel milage was awful, misfired, backfired... All sorta crazy stuff! So in August I began doing the timing job, it took me about 3/weeks as I worked on it when I could, I put the good stuff back, even metal tensioners and a Melling hv oil pump, new roller followers as well. Got everything installed after I got it timed correctly, then put it back together, got ready to crank, so I left the cps unplugged until it built oil pressure, and then spun it until I felt the oil had made it to the top of the engine then plugged the cps back in, hit the key and it fired right up, ran really well! I let it sit and idle for about 40-45 min, then went to drive around our block, got in the road and it was still showing the same symptoms as before just no chain rattle at start up and certainly no phaser noise!! I thought maybe the tps was bad so I replaced it, it tan better for a few miles then back to the same thing, so I replaced the throttle body, still same thing, after running a little better! Drove it to town to put gas in it, it was running well enough I felt it may straighten up after driving a little, but..boy was I ever wrong! I ran around town a few minutes before getting gas, finally got gas and right after it started running really bad, cutting off at stops, sluggish, no power, shifting badly! My AC just stopped working all together On my way home it got weaker and weaker and finally just died and never would start back up, as if it had no spark or fuel! Had it towed home where I have since Septembet 7 been racking my brain trying to figure this thing out!! I did find that if I let it sit a few days and then turned it over it would sometimes fire right up but shut right back down , no blown or burnt fuses or relays! All grounds checked and cleaned, replaced the fuel pump, fpdm, mad sensor..still no dice!! I think it's a PCM issue at this point, I have no theft light issues, the oil pressure would drop to zero if it idled below 1000rpm after warmed up, even after the new Melling HV pump, I replaced the oil pressure switch due to the gauge not moving while turning the engine over more than enough to build pressure, the gauge worked right after I installed the new switch, but only a couple Times, now the oil pressure gauge isnt working again, I noticed in my Cluster i cant access the self test mode to check for codes, in some spots of my LCD display I have --------- and nothing else. My truck has been down literally since August and I really, really need it running!! It's throwing no codes, I wonder if having the PCM powered down for 3 weeks or so may have finished killing it since it may have been going out when I bought it!! I have replaced about everything I can other than the PCM! I KNOW nothing else to do at this point! The cps seems to be ok since the tach gauge does move when cranking it.. New cps installed, I only got one key when it was dropped off to me and it's not an original Ford key but seems to work fine, before it just died on me back in September it would start at every turn of the key, but after it died on me that day.. it hasn't been driven one tenth of a mile and I need it badly!! Any ideas?

redfishtd

That oil pressure is a real bad telling thing .PCM is not causing that unless your cluster going bad . Your oil pressure switch is an idiot gauge it reads center for anything over 7psi , Question did you drop oil pan and clean oil pu screen /be very careful that oring connection between oil pump and pu . No good oring and pump will suck air .Cleaning oil pan is a must do , no telling what's in that oil pu screen we see lots of ground up fibers from broken guides, sometimes plastic from oil bottle seals etc .
Clusters have solder connection problems which may be inline with your display problems .
But first is your oil flow loss real /or what . you need a mechanical guage first . Is the engine noisy when it ran .
The pcm will shutdown the ac if its thinking engine not right, too hot etc . There are very few clues to look at here without it being running . We can't look at torque pro fuel pressure ,short term/long term fuel trims .
Shutting down the way it is sounds like fuel trims , which is determined by o2's and maf . You can have bad o2's , vacuum leaks , exhaust manifold leaks fooling o2's . You can have air box leaks /bad filter seals fooling maf flow .
Then you have the intake runner control and its linkage which is hard to see and work on .It seems you have multiple failures which makes it harder .
I suggest looking at runner control linkage just in case with a mirror or camera .
Maybe build a simple smoke machine diy you tube , test all the intake and airbox . Maybe be sure snorkel air intake clear .
But I also fear a compression test is going to have to be done .There is a lot to test and rule out . Your connections on cluster should be looked at . You do have cluster failure symptoms. The engine sensors go to the cluster ,oil ,temperature etc .
So many times we try to blame the black box -pcm but while it does happen its best to rule everything otherwise out .
Did you try to run with vcts unplugged . It should try to run in default mode .

WadeFX41970

I was sure to pull the pan and check/clean the pick up screen, added a new ring on the tube when the oil pump was changed, I did a vacume leak test right after replacing the timing components and all seemed to be well, I have tried running it with the vct's and cps unplugged. I tried cranking it yesterday for the first time in a week, I hit the key and it fired right up..but again shut right back down, I have tried cranking in Neutral, park, and about everything else I can come up with!! The fuel pump is working fine, seems I can smell gasoline when I turn it over, it's just not getting spark for some reason, I'm replacing the main power cable today so it has new battery connections on both sides of the battery, the current cable is lacking to say the least!! I bought a new genuine Motorcraft cable so it's all OEM! The cluster issue bothers me!