Hello everyone, I have a 1993 ford ranger XLT 2x4, with the 2.3 and the 5speed, 154,000 miles. I recently bought this truck, which I believe sat for a while. Previous owner was about to get it on the road, but had to sell it for financial reasons. He did coils, plugs, and wires.

Driving the truck, it seems way to slow, even for 100hp. Its getting around 17mpg, and pops and bangs like a racecar on decel (honestly sounds kinda cool). This has led me to believe its running rich.
For some reason there was no coolant temp sensor! So I just today replaced that, my CEL went away, and I took it for a drive to feel all 100 of those horses! But I was disappointed to find it still runs like crap.
The truck has never gotten up to proper temp according to the gauge, but I do get heat in the truck. I also just replaced the thermostat with a factory spec one.
The idle is rough, when its at proper rpm. A lot of the time it likes to idle around 900 to 1000, and letting off the clutch while driving it will only go down to 1100 most of the time. It will sometimes drop to the proper rpm of around 600 to 700, but when it does its really rough.
There was one day, out of the last 50 days I've driven it, where it ran like hot garbage, sputtering, stalling, bucking, and shooting to crazy rpms at idle. It would want to climb to 3000 rpm when let off clutch.
This led me to believe it was vacuum leak, but I tested the vacuum lines by unplugging the idle control module, and the truck dropped its rpms to 500, which is what its supposed to do if there aren't any vacuum leaks. I also sprayed them with soapy water, and no bubbles appeared.
I'm very stumped, there still are a few more things I could check, but I don't know what to look at next.
I have not tested the EGR valve, I've seen this be a problem for many, but wouldn't it throw a CEL or run lean if anything?
The MAF looks clean, although I haven't cleaned it with anything yet.
The truck sat for a while, it might be a leaky injector? Bad fuel pressure regulator?
It doesn't run terrible, just not good, accelerating is slow as all hell, but I have no clue how fast they are suppose to be. I have to be floored to keep going 65 up a small hill on the highway.
The idle is a little lopy if anything, like a cammed engine.
Any reply's would be much appreciated, thanks!

 

Welcome to the forum

First check for injector or FPR(fuel pressure regulator) leak
Clear Flooded Engine test
Key on engine OFF
Press gas pedal down to the floor and hold it down all the way(this turns OFF fuel injectors)
Try to start engine
It should just crank, no firing and no starting
This means no fuel leaking in

If engine fires/starts then check the Vacuum Hose on the FPR, if there is gasoline in that hose replace FPR


You have a Dual spark plug system for better power, but the engine only needs 4, ran that way from 1974 thru 1988
So I would test to see if all 8 spark plugs are working

Unplug the 3 wire connector on one coil pack
Start engine
Should run smooth, if it has a steady miss then one spark plug or wire on the working coil pack is bad

Shut off engine and repeat using the other coil pack
Dual spark adds more power but you can't tell when 1 spark plug fails, just slightly less power
So do this test at least once a year

Pull out computer and replace the 2 or 3 capacitors, they can fail after 20 years and causes odd running issues

 

Thanks for the reply! I just went outside to do the first test, I turned the key to on, held down the gas all the way, and cranked it, it hesitated, but started! Sent it to 4000 rpms cold but she'll live. I took the vacuum hose of the FPR, no gas inside. Could this mean fuel injectors? Or maybe still a FPR? I tried the test again with the same result, although I let off right before it started so I didn't send it to the moon again, but it still started.

 

Test for stretched throttle cable FIRST, more common that bad injectors

Key OFF
Use a stick against the seat to hold gas pedal down all the way
Go to engine and see if you can open throttle a bit more
If so then throttle cable is stretched, easy fix, Google: Ford Ranger Throttle Cable Mod

Computer needs to see WOT(wide open throttle) from the throttle sensor(TPS) or it won't shut off injectors

Over 5,000rpm won't hurt that engine, best horse power is at 4,600-4,800rpms, just FYI

 

I went back out with my dad, we confirmed that its WOT. Truck still started... I pulled the vacuum line again, no fuel. But I broke the plastic vacuum line . Going to have to fix that now.

 

OK

To find out, confirm, an injector is leaking you will do the same test BUT............
This time unplug BOTH coil packs, so NO SPARK

Loosen 4 spark plugs, 1 in each cylinder, easiest ones to get to
Cycle key off and on 3 times, this Primes fuel system 3 times
Crank engine over with gas pedal all the way down, 2 times

Pull out spark plugs, the one with WET tip has a leaking injector
If all 4 are WET then it may be a computer issue, not an injector issue

 

Thanks again for the help, I will do this test Sunday or Monday, got Christmas with the family tomorrow. I will report back with what I find.

 

I have some new discoveries, I did not do the injector test yet, but I have done some other things.

I completely forgot that I broke the vacuum line to the FPR, and drove the truck to work yesterday, it drove exactly the same.

I was thinking maybe the throttle position sensor was bad, since it wasn't detecting WOT. I unplugged the sensor, and drove the truck, it also drove the exact same, there was a little more hesitation to drop rpms after WOT, but other than that it made the same power, same rich condition, and had the same idle.
The truck is supposed to idle around 600-700 rpms, right? Its only a little rough around 600, but 700 and up is pretty smooth actually.
With the vacuum line still broken, I unplugged the IAC sensor, and the truck almost stalled, like it should. I was told this meant no vacuum leaks, but there was clearly a big one.

With this information, I have reason to believe its a TPS, but the big vacuum leak making the truck run no different is also strange.
I will do the injector test tomorrow, but I have a feeling that its something related to these two things.
When doing the flood test, it started and revved up like the computer had no idea it was in the flood test, not like it had a leaking injector or 2.

 

4cyl engines idle higher because they only fire every 180deg, so they vibrate below about 800rpms, so 750 maybe for warm idle, with manual trans
Cold idle should be 1,100+

All automatics have higher idles, add 50-100rpms

 

Ah ok, makes sense.
What do you think about these symptoms? Should I just replace the TPS and see if anything changes? I don't think its an expensive part.

 

Alright, some developments... Bad news. I did the injector test, no fuel on the spark plugs. I did a compression test while I was in there. 150 for cylinders 3 and 4, 140 for cylinder 2, and 100 for cylinder 1. There was oil on spark plug number 1, and a little on 2. None on 3 and 4. Am I looking at a bottom end issue or a head issue? Either way I think this is the cause of all of my problems. It may have not been running rich, but just letting the power stroke bleed out through an exhaust valve, hence the popping on decel. Please let me know your thoughts on what to do next. Thanks

 

Also the plugs looked perfect, didn't look dark like a rich condition would produce.

 

Cylinder 1 Is full of oil from what I can see inside.