I picked up a 04 FX4 Scab last week at a sale, and of course it ran great before I paid for it. Got it 15 miles down the road, pressed the brake to come to a stop, and it began to sputter and stalled.

Following the write up in these threads (1 2) I figured it was a bad TPS.

I figured I would replace the TPS and clean out the throttle body while I was in there.

I went to pull everything out this morning, and low and behold, there was a BRAND NEW FoMoCo throttle body assembly with a new TPS and ETC. The air filter was also a brand new MC filter.

I noticed some dirty water spots in the air filter housing, so I pulled the MAF sensor and it was covered in dirty water spots too, so I soaked four or five times with MAF cleaner and that seems to clean it up.

I also took off the PCV tube to check it, and it seemed to be a little gummed up, so I cleaned it out with carb cleaner. Lots of brown came out the other end. Since the PCV looks to be built into the crankcase I don't think it can easily be changed.

after drying and reassembly, the truck still rumbles and shudders when put into gear. It's fine in idle and at highway speed. If I brake semi hard or hard it'll stall out, if I brake slowly if won't stall most of the time.

It runs great when the engine is cold, but as soon as it fully warms up, the problems start back up.

It also feels like it up shifts ok, but it doesn't feel like it's downshifting properly. If I get up to highway speed (55+), then let off the gas and coast to a slower speed, it doesn't feel like it's downshifting and the RPMs stay high.

I'm not sure if the plugs have been changed from the factory plugs, and after reading the horror stories about broken plugs I'm just going to let the dealer do that next week.

The fuel filter looks new too.

Anyone have any idea what to try next?

 

cam phasers possibly.
get the engine at about 11-1200rpm and listen for a ticking sound.

i believe you have a spark plug problem. replace the plugs/coils and call it a day.

ive had both dont and while the phasers were annoying as hell they never resulted in a stall like your describing.

do you have access to a code reader? if your not getting a CEL you probably still have pending codes stored in the computer

 

I forgot to add no CEL and no stored codes.

There's no ticking sound at 1100-1200 rpm either in idle or in gear.

I'm hoping it's the plugs. The amount of road dirt around the coils versus around areas that where recently worked on (like the throttle body) make me think they're factory plugs.

 

Sounds like someone was already throwing things at it. hook a fuel pressure gauge up to it and see if your fuel pressure is dropping out of spec. before it stalls. I've seen this a couple times before, just not on these trucks, where the fuel pump is bad and can't keep pressure at low idle. This is just one thing to look at since I'm not sure what all else has been done. good luck and report back what the fix is to help others.

 

I take back what I said about the fuel filter being new. When I dropped the box to disconnect fuel power, it had about 2 pounds of sand and rocks in it and I'm guessing only a fool would switch fuel filters without depressurizing the system.

I'm going to try a new fuel filter and rent the appropriate fuel pressure tester tomorrow. The one I have doesn't have the right connectors. I can't believe Ford did away with the valve on the fuel rail that make pressure testing easy.

 

How does the FPDM look? They are noted for corrosion issues.

 

the truck is still at the dealership after getting the plugs changed. 3 of them broke, so that's a $450 bill.

The tech noted a knocking in the engine, and also an a problem with the transmission going into overdrive too early. It's still not throwing any codes, even to Ford's computers. They're going to do a diagnostic to see what all the issues are and get back to me.

 

just got off the phone with the dealer and I think I'm going to be sick.

The transmission valve body needs to be dropped and the check ***** need to be replaced.

And the worst part: the engine is sludged up everywhere, which is keeping the oil pressure low. They're recommending a new engine if I plan on keeping the truck.

Any thoughts? I can eat the tranny bill, but a new engine....

 

Before replacing the engine it might worth trying AutoRx. Google AutoRx, you can only get it online but most of the folks here highly recommend it.
Just curious but what are they saying the actual low oil pressure is? Ford tends to think oil pressure cannot be below 30 psi. The VCT system will still operate at 20 psi and below. I believe oil pressure readings should be taken at cold start up, oil temp @ operating temp and engine @ 2000 PRM.

 

The service dept has closed, so I'll have to get the psi numbers in the morning.

Thanks, the AutoRX looks like miracle stuff.

I'm guessing the clogged PCV tube was full of sludge. When I ran carb cleaner through it oil colored fluid came out the other end.

When I get the truck back I'll check the FPDM.

 

Oil pressure at 2000 rpm is 50 psi.

The service guy I'm working with is going to write up a full quote for all the work that needs to the done, and I'm going to work on the seller to either take the truck back or throw some money at me for the work.

If they won't play ball, then I guess I'll try the AutoRX.

 

I don't mean to hijack the thread but am I understanding correctly in that the chattering at around 1000-1200 RPM is from a bad phaser or phasers? Mine flat out sings a tune when it's revved to that RPM range and it seems as though I've lost a bit of power too.