1986 Ford Ranger vehicle looses power on hills

I would suspect low fuel pressure (weak pump?) Or weak ignition system.

Start by doing a fuel pressure test. I think with engine running you should get around 35-45 psi.

1. Pressure test your cooling system as well as the radiator cap. When you do so check your oil level: if it's higher you probably have a leaky intake manifold gasket.
If you're loosing a lot of pressure in a short period of time and are unable to find any external leak, you can suspect a leaky head gasket, or cracked cylinder head.
I assume you check all the 'usual' areas for external leaks already (water pump, hoses, radiator, etc). Have you checked your engine drain plugs? You should have two of them (one on each side of the engine).
About the block sealer now. Some people say it's okay, some say it's not. In some cases it may work if the leak is very small, but if too big it won't work at all. It's not a permanent fix anyway.

2.
For your EGR problem do the following:
Apply 5-10 in hg to the egr vacuum nipple with a vacuum hand pump. If.
-engine doesn't stall or run roughly
-idle speed does not drop by more than 100 rpm
-idle speed doesn't return to normal after vacuum is removed
. Replace the egr valve.

21: engine coolant temperature (ECT) out of self-test range
24: air charge temperature (ACT) sensor out of self-test range
Check these sensors and replace if necessary.

You sound pretty much sold on the idea of using some sealer.
If you're lucky it fixes the leak. Momentarily at least.
However, it probably won't help if you're dealing with a blown head gasket, or something major like that.
It could also do more bad than good by plugging areas that don't need to be plugged.
I know you would like a definite answer about this, but the truth is it's impossible to say if a sealer will fix your problem or not, or if it will make it worse. Some people have had good results, but other called the sealer company to express their disatisfaction (to put it nicely).
What I'm saying is do some research about these products before you make a decision.
By the way, have you done a pressure test on the cooling system? It may help finding the leak.
You could also check for exhaust gases in the coolant with a tester.
You should also check the compression in each cylinder.

Clearing codes now.I'm not sure what haynes recommends; have you tried to disconnect the battery? It will delete all the data and your car may drive a little different for a while, but once the ecm relearns everything you should be fine. Unless you haven't fixed the problems and the codes come back.

Good job on the radiator cap! 7 psi was definitely too low. If your system holds the pressure, you shouldn't have any leak, so no need for that sealer ;)
One problem out of the way!

Check the electrical connector at the solenoid; is it loose, rusty, high resistance? Also check your ground connection.
Also, back in 1986 Ford started introducing the PFE sensor. Is that the sensor you replaced?
If not I would check it out, and maybe replace it.

If you have vacuum at the solenoid but very little vacuum at the egr valve when the solenoid is powered on, the problem would lay either in the solenoid itself, or the wiring, or possibly the computer control.
Also, have you made sure that the vent port on the solenoid is not plugged?
You may have a piece of filter foam in there; unless you replaced it recently, I would go ahead and replace it; it may be the source of all your egr problem.

Your EGR valve is not " �engaged' until the engine is warm and under load, you are correct; however, you may still have a little bit of vacuum that passes the solenoid (eventhough it is not powered on) and gets to the valve, which from what you previously said is what you're experiencing.
What I'm thinking is that your solenoid is not working right; since you replaced it, the problem probably lies either in the wiring between the solenoid and the ecm, or a connector, or in the ecm itself (the solenoid is grounded inside the PCM through a Quad driver).
Basically your EVP voltage doesn't change like expected when the solenoid is supposedly powered on (hence code 33); it is probably the result of the solenoid not cycling as expected (hence code 84).
The 12v supply you get at one terminal is normal, however I don't think you would have voltage at the other terminal with key on, engine off.
Check the connector and wiring to the ECM and replace if necessary. If the wiring and connector are good, the problem may be in the pin at the PCM (#33 I believe) or the driver in the computer itself. Since you already tried to replace a bunch of stuff, I would try to replace the wiring/harness between the solenoid and the ecm; if it fails to fix the problem, your ecm (quad relay) would likely be defective, assuming all the tests and repairs mentioned in all the previous posts were done right. If you get to this point, I'd suggest you take your truck to a Ford technician for an accurate diagnostic, before replacing the ecm.

Hope this help.

Hi there,

- Do you still have the egr codes? A problem with a knock sensor can be related to a defective egr system...
Also, we talked a good bit about the egr because of the codes you were getting, but have you ever checked your timing and compression?

- You can start with a good injectors cleaner; it may help. Make sure you fill your tank with good quality gas from a reputable company: cheap gas contains less additives which can quickly result in your injection system getting clogged-up (You’ve seen the Shell commercial haven’t you?). Moreover, cheap gas may not have the proper octane level which can result in your engine detonating.

You could also have your injectors cleaned at a shop either by running some cleaner at the fuel rail while the engine is running, or by removing the injectors altogether.
The " �off-car’ cleaning option would give the best result and your injectors could be flow tested; but it is more expensive.
To know for sure if you have dirty injectors, you can perform a fuel pressure drop test:
Here is the procedure you can find online:
“This test measures the drop in static system fuel pressure when each injector is energized. The amount of pressure drop for each injector is then compared to see if the injectors are dirty and need to be cleaned or replaced. This test requires an "injector pulser" ($90 on Amazon) tool to energize the injectors.
To perform this test, turn the key on or energize the fuel pump for a few seconds to build up static pressure in the fuel system. Then turn the key off, pulse one injector for the specified time and note the pressure drop for that injector. Turn the key back on to rebuild static pressure and repeat the test for each of the remaining injectors.
An injector that is pulsed 100 times for five milliseconds should produce a minimum pressure drop of about 1 to 3 psi, and no more than 5 to 7 psi, depending on the application.
The difference in pressure drop between all the injectors should be 2 psi or less. If you see more than 3 psi difference between the highest and lowest readings, the injectors are dirty and need to be cleaned or replaced.
If you see no pressure drop when an injector is energized, the injector is clogged or defective and needs to be replaced. If the pressure gauge needle bounces, the injector is sticking."

- As far as the wiring diagrams you could check " �alldatadiy’ or " �Mitchell1’. They both offer factory wiring diagram as well as just about any info you need to fix your car.

I understand; it's hard to find a really good mechanic who actually does real troubleshooting instead of guessing and 'shotgunning' parts at the car.

I think I'm with you; I'm starting to wonder if you really have an egr problem. That's why I mentioned timing and compression.

After I posted my response last night I did more research myself about the knock sensor (I don't know the location of all the knock sensors for all the models and brands), and I could not find anything about it for a 1986 Ranger. So I went to my garage looking for my Haynes manual buried underneath a pile of books/tools/cra@#. After a couple of minutes of digging, I finally found it and looked what Haynes had to say about this sensor. Well... Nothing I guess because I didn't find anything about it. It didn't even show code 25.

Hopefully, cleaning your injectors will help; it can't hurt anyway.

Let me know if replacing the thermostat helps.
If replacing the thermostat doesn't fix your low heat problem, check your heater core as it could be getting clogged.

As far as your low reading on the temp gauge, you may also want to check your fan clutch: it may be defective resulting in overcooling.

Let me know how it goes; I'm curious to hear if your problem was related to a closed loop open loop condition.
Also maybe your termperature switch/coolant sensor is getting bad.