So my 99 2.5 rcsb has been stalling out under loads, particularly when the A/C is on. It's stalled when warm, cold, engaging Drive or Reverse, and it steering does it at least once a day. There's a missing elbow to a vacuum line at the driver side (looks RABS related). The truck had the CAT melt off and now it's laying in my bed with the O2 sensor, don't know if that relates.

This truck sees 100 miles a day through the mountains, 5-7 days a week. It only has 140,000 miles on it, I put 40,000 on it in the last year with no issues. The truck is very much showing age (needs almost everything), but I'd like to keep the basics going.

 

Well the missing vacuum line elbow will corrupt fuel trim & that along with the daily 100 mile drive cycle can be rough on the engine & cat converter, especially if there's no longer a O2 sensor providing feedback to the computer on how it's doing with controlling fuel trim it's likely had to revert back to it's programmed in value which is also a little rich, so you've also likely been ignoring a lit CEL for a while.

With a daily 100 mile drive cycle through the mountains with no fuel trim control is pure torture to the engine, I'm surprised it's still putting up with it.

With that mileage, a number of scheduled maintenance replacement items are over due.
Things like upstream O2 sensors, plugs, wires, fuel filter, air filter, PCV valve & maybe it's rubber connecting hose & grommet if they're dry rotted, all fluids, all of which you can do yourself.

Replacing the down pipe & cat converter & determining if the melt down of the cat converter & the resultant excessive exhaust back pressure has done damage to the engine may take some expert diagnosis & should be done by a trusted pro, Before any costly resurrection is attempted.

Some thoughts for consideration, let us know how it goes & good luck, cause your likely gonna need Truck Loads of it....no pun intended!!!!

 

Truck developed a misfire on cylinder 1 last night. I'm parking it. The ODO only reads 140,000 miles, but I don't believe it. Still interested to get it going for a weekend truck but, not looking at investing too much. I'd like to start pulling it apart myself and see what I really have here though. Might give me something to do after work.

 

Ok, well you might consider beginning with a compression check on each cylinder, to kinda get an idea of the rings & valve seat condition, then decide what to do from there.
Let us know what you find.

 

after completing the compression check, reusults are as follows.


Cylinder 4- 180 psi, holds.
Cylinder 3- 180psi, holds,
Cylinder 2- 180 psi, holds
Cylinder 1-160 psi, holds.

The back 3 plugs were black and dry, and the looked a bit large, although I didn't check them. Plug 1 was brown and not as black. Dry, and the gap looked about the same.

Upon tear down as well, I've found the recirculating pipe from the header to the EGR is bent and the DPFE sensor has a broken connection on the REF side. PCV hose is garbage. Vacuum has been plugged but still haven't gotten a replacement elbow.


Codes are 301 and 171 right now. As I mention before, the more I look the more I find.

 

Ok good feedback on the compression check. All are surprisingly good with the mileage you say it has. Seeing as how the exhaust got so dang hot I was concerned that excessive exhaust back pressure & the resultant heat may have compromised something in the engine but right now it seems maybe not.

Kinda sounds like replacing some long over due scheduled maintenance parts may be all it needs to bring it up to date on all past & present due scheduled maintenance call outs.

Most of the items you've mentioned are just common repair/maintenance parts any one would have to do with the kind of mileage this puppy has.

 

I've got all the parts except for those related to the exhaust (let the pros have that headache). I'm gonna work on this truck all night tonight and try to get it as good as it'll get before dropping it at a muffler shop.

 

got the truck back together and fired it up. The wires likely solved the misfire as it's not doing it anymore. However, I'm about todo the fuel filter, but it's way over metering it at start up because you gotta put your foot to the floor to start it, and then it idles and runs rough like it used to. No misfire though. That's good. Got the O2 for the muffler shop. Drop it off tonight, hopefully running right.

 

Ok will be interesting to hear how it runs after the exhaust system is repaired & the new O2 sensor is installed.

If your seeing such a corrupt/over fueling that you have to floor the accelerator to start it, the CEL should be lit with a fuel trim code showing rich trim. Flooring the gas pedal when cranking the engine, has the computer turn the fuel pump off, as this is the procedure for clearing a flooded engine.
All that raw/unburned fuel being dumped into the exhaust, up stream of the cat converter, means it'll overheat right away & melt down, starting the problem all over again.

SO, before driving it, you need to find out what is wrong & put it right without delay.

If you have a dirty/stuck open fuel injector, or out of control fuel pressure, they can be checked individually before driving.

You can measure fuel pressure with a gauge at the under hood fuel rail Schrader valve test port & the fuel injectors can be removed, for viewing to see if any have a runny nose when the fuel pump pressurizes the system at KOEO.

It's past time, so have the timing belt, tensioner & idler pulley been replaced?

Same for the PCV valve. If this is the first time for it since new, you may be eligible for a no cost replacement from Ford. Have the Dealer run the vehicle VIN to see.

 

changed the fuel filter, no improvement. Pulled the downstream O2 and it's a nice white color. Doesn't look too old and it came out pretty easy. No heat involved. Trying to get the upstream out on my own so I can see if it improves anything before investing on the exhaust.

Fixed all vacuum issues. Still need the EGR recirc tube but I'll leave the up to the exhaust guys if I can get this to smooth out a little.

Will the truck be able to work with a damaged DPFE connection to the recirculating tube?

Cleaned every sensor last night. Got a new EGR hose on it. Basically hose, hoses could and injectors, and I'll have a new top end.

any suggestions on get the upstream O2 out?

 

On the O2 sensor, try a heat/cool cycle with a 50/50 mix of tranny fluid/acetone as a rust buster on the cool down cycle to see if the heat will draw it in & see how it goes.

Computer doesn't call for, or apply EGR at idle.

Keep pecking away at & fixing known problems & you'll likely continue to see improvements. Fuel trim tables are likely corrupt, so if you haven't already done so, disconnect the battery B- cable to wipe the KAM in which the tables are stored & see if it makes a positive difference.

 

replaced the #1 injector and the truck smoothed out pretty well. Still feels like it could use something else because she's a bit weak. But it's not choking or stalling. Still not starting easy. Fuel filter is new as well. Been pulling the cable after each start to save the battery so it should have reset many times.

 

I think I'm gonna drop it at the muffler shop tonight and let them do the rest.

 

Ok, let us know how it goes. Any luck getting the O2 sensor out?

 

Truck runs good but is still refused to move. What's next?