'99 2.5 5 speed stalling

I have a 1999 2.5 5 speed with an issue. This mainly happens when it is cold.

When cold, if I try to drive the truck it wants to stall when coming to a stop. It doesn't idle rough or shake it just cuts off when coming to a stop. This frequently happens when cold while coming to a stop or putting the clutch in while yielding for a turn. As you can imagine it is a bit dangerous as I lose power brakes and steering.

If I let the truck reach operating temperature it won't stall, however if I rev it or put the clutch in just after the top end of a gear it wants to idle rough and sounds as if it is missing on a cylinder or two.

I have replaced:
-upper and lower intake gaskets
-IAC and gasket
-EGR gasket (and cleaned the ports)
-Valve cover gasket
-Cleaned and replaced the lifters (they were noisy)
-Cleaned the MAF
-Replaced fuel pump
-Replaced Filter
-Cleaned injectors
-Cleaned fuel lines
-Filled up with 93 Octane (back on 87 now with the same issue)
-Checked all vacuum hoses and checked vacuum while at idle
- NO CHECK ENGINE LIGHT


I did notice that if I rev it while the vacuum gauge is hooked up, it will come back to idle but will idle rough and vaccum drops dramatically.


It appears this is common with these trucks, but I have not read of anyone solving the issue yet. Most suggestions just say "let it warm up" or "don't rev it high". However these are obviously not solutions to a problem and during rush hour traffic I need to be able to count on getting the vehicle up to speed quickly without it stalling or idling rough.

If it keeps this up maybe it's just time for a LS swap, or 5.0? Any suggestions? Thanks!

You have done a lot.
Vacuum gauge would drop if engine is misfiring.
What is warm engine vacuum at idle?
Gas engines run 17" to21" usually

If you can get/rent an OBD II scanner you could check the info the computer is seeing and basing it's engine operation on.

Engine computers are simple devices, but like all computers the standard rules apply, the main one is "garbage in = garbage out".

Computer bases it's Choke Mode(open loop) mainly on coolant temp, this info comes from the ECT sensor, a TWO wire sensor only used by the computer(there is a similar looking ONE wire sender used by the dash board temp gauge).
Choke Mode is needed on all fuel injected engines because a Choke Plate won't work unless there are jets to suck extra fuel out of.

When you turn on the key the computer checks the ECT temp, if cold the computer will open injectors longer(rich mix) and set IAC Valve for idle above 1,100rpms, it will also advance spark timing, same as a Choke Plate did on a carb.
Cold engines need more fuel and will tend to stall at lower RPMs.
The colder it is the more fuel it will need, this is because colder air is denser than warmer air, the 14:1 air to fuel ratio is based on oxygen content, denser air has more oxygen, so needs more fuel, this is why vehicle can feel "peppier" in the winter, and why MPG goes down, you use more fuel so have more power.

The MAF sensor on your '99 should have 6 wires, this means it reads air flow AND air temperature(IAT sensor), air temp is not a big variable, but your issue is also not a big issue, like a no start, so a small variable could cause the stall.

Also when in Choke Mode(open loop) the O2 sensors can't be used, they need to get above 650degF to function, so computer bases air/fuel mix on MAF, ECT and IAT sensors, it has no feed back on lean or rich from O2 sensors, so it couldn't set a lean or rich code

Hooking up the OBD II scanner will show you what the computer "sees" when engine is cold.
It could be the ECT sensor is reading 40degF(correct) on cold start and then after a minute warm up it jumps to 150degF(incorrect) so computer leans out the fuel too soon and lowers idle too low, so you get stalling.
Same for IAT sensor, it could be reporting wrong temp, causing a lean or rich stall at low RPMs.

A total failure in one of these sensor would set a code, but reporting incorrect temp wouldn't in most cases because computer has no way to know they are wrong.

You can also tell alot about cold engine operation just from idle speed, computer uses IAC Valve for this, so watch RPMs at idle as engine warms up, the idle should drop slowly from 1,100-1,200rpms as engine slowly warms up, there should be no sudden drop to say 850 after a minute or so
On average it takes a cold engine 5 to 8 minutes to warm up, and idle should slowly drop during that time, no sudden changes

I appreciate the help, that was my next step, I've been researching the most cost effective way to go about procuring a way to take a look into what the computer sees. I haven't found a "cheap" solution yet, but I may try this: https://www.autoenginuity.com/products/oe-coverage-options/ford-family-ei01.html

I also have a 7.3 excursion so that would be handy to have anyway.

I also replaced both the ECT sender and sensor, as this issue existed before replacing them. I just failed to list it. I am also going to check the slave cylinder, it has become progressively harder to shift and does not seem to disengage until I have the pedal basically in the carpet now. The clutch, slave, master, and flywheel are all new, but new parts fail sometime too.

I imagine if the slave is failing this would definitely cause or at least worsen a stall with clutch in issue if it wasn't actually being taken out of gear.

Bringing this back from the dead, truck is still stalling when the throttle is closed and will idle rough or stall if revved and let off quickly:
-Replaced the MAF thinking it was reading low, and not failing enough to set a light.
-No change
-Scanned for codes, p0302/p0303 shows up only when the rough idle condition happens. Then it clears after normal driving.

Unfortunately I have no way to view live data, but does this sounds familiar to anyone? I've seen a couple of threads mentioning worn valve guides or collapsed lifters, blown headgasket, etc. Are these trucks really this problematic?

Thanks

You asked:Are these trucks really this problematic?

No. They are relatively problem free if fed oil changes & proper coolant maintenance. They don't ask for much, and will regularly go 300k without problems or major work.

I would think about checking the TPS. Throttle Position Sensor may be fooling the computer as to how far open you have the throttle plate, and thus cutting fuel too much too quickly. I know that some have both a MAP and a MAF. The MAP will sense manifold(intake) pressure or vacuum, and report to the computer. If the vacuum is low, i.e., full wide open throttle, the computer will add more fuel, and the vacuum operated fuel pressure regulator will raise fuel pressure & thus injector flow. High vacuum, as when the throttle plate slams closed, will generally cause chop to the fuel flow as there is no air to burn it...
If your pressure is correct, and the ECT & ACT(air temp) sensors functional, and the MAF clean, along with good mechanical, then it should work. The codes 02 & 03 are misfire on the center two cylinders. Have you had any coolant loss or high pressure symptoms? Those two are adjacent, and might have a head gasket problem. If the engine idles smoothly, I would doubt that occurring.
Have you checked that the PCV is working properly? It could be messing with the idle mix.
tom

While electronic scanners are neat tools, a $25 vacuum gauge can tell you alot about any engine.

All gasoline engines have 3 basic needs to run smoothly
Spark, at the right time
Fuel, in the correct 14:1 air:fuel mix
Compression, above 90psi, 2.5l should be above 150psi

Adding electronics to an engine makes it more reliable, contrary to what you may think at this time, lol.
But all they really do is to take away the moving parts that wore out or had to be adjusted all the time, i.e. points/distributors, and carburetors.

The 2.0l/2.3l/2.5l Lima engines are/were very reliable, but like all engines parts do wear out over time

Have a look at a spark plug from #2 and #3, the misfiring at idle cylinders.

Could be a small intake gasket leak effecting the two center cylinders, at idle/lower rpms there is enough of an air leak to cause lean misfires, as fuel level increases(higher rpm) the air leak has less of an effect and cylinders start to fire.

Does it start right back up and idle fine or does it crank fast and sound funny before starting?

It actually seems to crank slower, almost like a dying battery. Then when it does start, it will continue to run rough and suddenly recover 10-15 seconds later.

-Vacuum is good, unless I cause the rough idle issue by revving and then snapping the throttle closed.
-Radiator is new, the plastic side on the old one split. No coolant loss that I've noted.
-I have noticed steam/water when the truck is running, but not an abnormal amount and not the color you get from a blown headgasket.
-Compression is the only thing I've not tested, sounds like time to buy a kit!

I bought a OBDII scanner on e-bay for $40. code reads, live scan, freeze frame, ect. I've used it for about 5yrs now no issues. It's an orange unit with a black zipper case. Called "OBDII Can". Comparable units at the auto stores are $100.
You might want to carefully check the air box and tube, vacuum tubes and hoses. Check the routing and for cracked, broken or loose fittings. Sometimes its the simple things. Air flow and vacuum seems to make a lot of difference in these engines. I put in a K&N filter and tube on my Ranger. I have the same year and engine as you do. Kind of an expensive upgrade for 5 hspower but I carry a lot of weight in my truck. The filter fell off a couple of times and made it stall and run rough.

Being my ~26th vehicle, I was a little frustrated not being able to track the problem down. I've checked vacuum, fuel pressure, took my trusty MM to every sensor possible, etc.

End result is: Recessed Valves

I've spent roughly $1000 in maintenance items and then repairs once I came across the stalling/rough idle after closed throttle/clutch in scenarios.

I came across a thread that was very detailed in the description of their issue and the root cause. I then found dozens more posts from 2.5 owners with the same issues. I then connected the dots as I previously tried to diagnose a lifter tap issue while digging around under the valve cover.

My problem is recessed valves, with 170k miles on it - I just wanted to update the thread here in case anyone happens to come across it hoping to find a fix.

elementaltoad said:

Being my ~26th vehicle, I was a little frustrated not being able to track the problem down. I've checked vacuum, fuel pressure, took my trusty MM to every sensor possible, etc.

End result is: Recessed Valves

I've spent roughly $1000 in maintenance items and then repairs once I came across the stalling/rough idle after closed throttle/clutch in scenarios.

I came across a thread that was very detailed in the description of their issue and the root cause. I then found dozens more posts from 2.5 owners with the same issues. I then connected the dots as I previously tried to diagnose a lifter tap issue while digging around under the valve cover.

My problem is recessed valves, with 170k miles on it - I just wanted to update the thread here in case anyone happens to come across it hoping to find a fix.

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That's what I was suspecting. I usually see them stall cold and then have no compression for a while. The start up and run fine like nothing happened.

BRUTUS_T_HOG said:

That's what I was suspecting. I usually see them stall cold and then have no compression for a while. The start up and run fine like nothing happened.

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That's exactly what it does, it's not a lot of fun stalling out in the middle of traffic, or in the middle of a hard turn leaving work.

I'm not real certain what to do with it. I don't want to put a used engine or head in that will likely have the same issue immediately, or in short order. I think the only right way to fix this is to buy a new manufacture head, or.....put a V8 in it.

I went with a new head on my 97 2.3L because I wasn't happy with the remain heads I had looked at. I'm very happy with the new head and it's said to be an improved casting over the factory head. The same guy I bought my new head from also sells them for the 2.5L here's a link.
http://www.ebay.com/itm/NEW-2-5-FORD-RANGER-SOHC-CYLINDER-HEAD-1998-2001-8-VALVE-2-PLUG-SMALL-SPRINGS-/351310474394?pt=Motors_Car_Truck_Parts_Accessories&hash=item51cbbc6c9a&vxp=mtr

Thanks for the link, that's not a bad deal. I'm trying to decide though, if it is worth trying to install a new head with 172k on the bottom end. I'd hate to rebuild the top end only to have the bearings roll or find the bores too worn. It doesn't burn oil though, and I know the bottom end is said to be fairly tough.

elementaltoad said:

Thanks for the link, that's not a bad deal. I'm trying to decide though, if it is worth trying to install a new head with 172k on the bottom end. I'd hate to rebuild the top end only to have the bearings roll or find the bores too worn. It doesn't burn oil though, and I know the bottom end is said to be fairly tough.

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If you can do the work yourself you can send the head to good machine shop and have it rebuilt like new. I wouldn't be worried about 172k unless you take the valve cover off and find evidence of oil sludge.