At the end of my Rope... Gutless and no A/C

all the Relays checked out as good, Didn't get around to doing the EGR just yet. But i got half way home before the probably came back after work. going to run some sea foam and give it a few days to see if it clears up at all.
If not i'll continue with the EGR and check my headers.

 

It happens regardless if the A/C is on or not, I haven't touched the A/C in a few days and it keeps happening.
The lack of power starts after about 10 seconds to 4 minutes of driving the Truck, It's really weird that it varies so much.
it feels like the engine shifts to a difference RPM right as the problem comes back, or that could be the whole issue.
I haven't got down down and dirty with the A/C system quiet yet.
Nothing leaks and I replaced the Thermostat when i did a complete flush of the radiator and what not (not really familiar with the lingo)
I've check if all the grounds are clean and connected correctly.
I do need to add a ground going from the Frame to the bed of the truck, as recommended from my Father.
Although no one is perfect and I might have missed a ground or two, always pays to double check everything.
I plan to do so tomorrow when I get around to messing with the EGR.
The guy my dad bought the truck from spliced into a lot of the hoses on this thing to try and install nos or nitro. so i've been dealing with little things here and there.

Who knows, I could be explaining the whole thing incorrectly. After changing the fuel pump and have a decent amount of power back. but when I floor it it shifts up but doesn't gain speed.
Which I know with an older truck I should rarely do that, but the fact that it's not working properly concerns me.

 

Yet another thing I forgot to add to the list, Put a new distributor cap, spark plugs and all the wires between that were new when we bought the truck.
Not to mention the radiator is brand new as well. I'm leaning towards maybe it's the fuel injectors, EGR, or the ground/wiring to the new MAF?
regardless I need to double check everything I've done already and start checking voltages and grounds.

 

Have you replaced the fuel filter? it shouldn't have anything to do with the AC not coming on but it explains the lack of power.

Edit: Nevermind, skipped over the filter being replaced when the pump was.

 

oddly enough the first time it happened the first thing I did was replace the fuel filter and it fixed the issue for a little while. I cleaned out the new one I bought after a few days and it didn't make a difference.
By cleaned out I mean used a air compressor blow the opposite way of the flow.
All this being said and done I am going to shoot my foot if a new Fuel filter will fix the issue.

I've already fallen in love and given to much time and money to this truck to give up!
Even if I have to work on it daily!
maybe it would be worth mentioning this is my first Car/Truck? I've owned nothing but motorcycles before this Taco.
but I have worked on plenty of cars with my Father.

That being said It's not that i'm not mechanically inclined, just when it comes to electronics and all the different parts it takes me a little while to get familiar with them.
If I was told to pull the engine out and the transmission and put it all back together correctly I could given the time.

but as it stands I need to check the EGR tomorrow along with the headers and grounds again. Unless the seafoam fixes my issue

 

So, I'm not sure about the RPM shift you mentioned, that sounds peculiar. But I had a similar issue with no power on mine. I took apart the EGR system (valve, vacuum lines, and upper intake) and found a few things wrong. The EGR port in the upper intake was completely clogged and the valve had so much carbon build up, that it was stuck also. On top of these, someone had dove into the EGR before me and the vacuum lines were not routed to the correct places... Cleaned the intake with some carb cleaner, rerouted the vacuum lines and ran some seafoam through it and it's been great ever since. I should note mine was accompanied by a low EGR flow CEL...

It sounds like your issue is rooted elsewhere, but with a can of carb cleaner, seafoam and an hour or so you could rule out your intake as the issue.

 

sounds like the tps to me

 

Does the AC work at all? Perhaps the condensor is binding up and robbing power.

 

If there is a seperate belt that runs the AC by itself, remove that belt and see how it runs.

 

Finally!

 

I think being able to fix your own truck is an absolutely great skill to have. Looking at what you have replaced so far, I don't see that you are throwing parts at it. I know there are plenty of mechanics that take educated guesses when doing repairs, and get it wrong. Don't give up!

Remember: fuel, air, spark

Sounds like the things you have done so far to fuel system have made some differences, so keep going. I would check the fuel lines from the tank to the fuel rail, maybe the flow is restricted, line hit by a rock
Maybe the fuel pressure regulator is bad. I think you can check the flow by taking a line off and routing it to a bucket.
I would also verify the pump is not sucking air, is the pump pickup ok.

 

I literally signed up to this forum after reading this, as a Red Seal Journeyman Technician, this is beyond painful to read.

If I were you, and this is only a suggestion... maybe attempt to connect a diagnostic scan tool, to, your OBD2 equipped vehicle (this is for diagnosing issues such as this.......)

After step 1. Attempt to monitor your crank position sensor, aka the sensor that tells the vehicles ECM (Engine Control Module) the RPM (Revolutions Per Minute) of the crankshaft. If you're losing this signal, typical after the engine reaches operating temps.. (Your issue is after driving the vehicle, correct?), your ECM will enter "Limp Mode". Typically sending the Fuel and Spark timing into a predetermined algorithm. While the vehicle will still
operate, it will only perform well enough to get your vehicle to someone that can repair it correctly.

So, if I were you, which I'm not, I would start there.

 

Have you checked the valve lash? A leak down test could turn up some leaking valves, that would rob some power.

 

One other thought, I snapped a timing belt on my 92 integra. The shop aligned the cams with bottom dead center instead of top dead center. The car ran great at start up and once it warmed up barely idled and had minimal power.

 

He would have probably stated he did a Timing Belt in his thread, semi surprised he hasn't thrown one at it to fix this lol.

Valve lash would need to be pretty far out, and it would most likely cause issues during start up and immediately after start up.

Crank Position Sensor and/or Throttle Position Sensor is where I'd be looking.

 

First thing to do is a compression test, including a leakdown test. Just to determine the basic condition of rings and valves.

If the compression/leakdown are good, then check all the hoses that have been ham fisted. Vacumn leaks are killer for power loss, and we don't know what he may have cobbled up.

At idle, remove one plug wire at a time and make sure the running is affected. If you pull a wire and nothing changes, you've found a dead cylinder.

Distributor cap. That means there is a distributor (doh!). So the base timing could be very retarded. The distributor lock down could be loose allowing moving and base timing change. There should be a procedure that will allow you to disable the timing control done by the ECU. Ususally a jumper in a diagnostic port. You then set the idle correctly, then set and lock down the base timing. Then bring the ECU back into play, and it will do it's advance/retard work from the base you established.

Sorry I can't tell you more detail on your Tacoma, but I've done that many times on various older Hondas and Mazdas, so I'm sure Toyota has a similar set up. Retarded timing make a vehicle run awful. Jumpy timing will drive you nuts. And yes, with the timing retarded, adding load, like AC, will be like tossing out an anchor.

 

Sorry I haven't check back in 2 days guys, life has been crazy and I won't be able to do anything until Wednesday... I'm going to add to the list of everything people have recommended. I really appreciate the directions you guys have given me! I'll do a follow up post later in the week. Sorry for vanishing.

 

And another couple of weeks have slid by. Any updates?

We like knowing final results, knowledge base for the good of the order and all that.

 

The guy has a new to him truck. He wants to work on it. He's at least going through things logically and trying the next step. And truthfully he hasn't thrown much money at it other than the new MAF. The rest of it is just mostly his time.

This is what you'd charge him 3x for? "Probably" have a "bad sensor..." Seems pretty vague. And ironically like you'd just be taking shots in the dark and throwing his money at it.

 

I'm not sure if I followed everything that's happened closely enough but I've got some comments from my own experiences and ideas. Number 8 (bell cranks) definitely hurt my truck's power.

1. You changed the distributor cap. My points were gone AND the rotator tip inside exploded. This didn't make the truck lose any power, it just had trouble starting. As far as firing make sure the order is correct.
2. I agree with whoever said remove the AC belt. Heck, after testing that remove the power steering belt too. After that try removing the alternator belt. That's all (3) belts there are.
3. A bad O2 sensor will just pour gas out, but you should have a check engine light and a gas gauge that drops at twice the normal rate.
4. Check to make sure a critter hasn't plugged the intake from in front of the air intake filter, i.e. try to make sure the intake tube that's inside the fender is clear.
5. Here's an idea that is really out there: is it possible the starter is always in the flywheel? Backdriving the starter would definitely put a load on the motor, especially as it heats up as you drive.
6. My radiator fan clutch stayed engaged from the start, and then disconnected (which is the opposite of how it's actually supposed to work). After first starting the engine, it would sound really loud, but then after a few minutes of driving the engine would be silent. It's clutch is controlled by a heat sensitive metal.
7. My truck's first engine a coolant leak in one cylinder, but it did not lack any power that I noticed, but once again it was very hard to start. You would've known when you checked your plugs.
8. Knock the f-ing bell cranks loose on your rear brake drums and ensure your parking brake cable isn't engaged. Very, very noticeable lack in power with the drums even slightly engaged. I hate drum brakes.
9. Unlock your front hubs if they're manual; lots of mass to turn.

My logic's a bit different from the other suggestions I've read on here. My approach would be to remove "loads" (in such a way you can drive it temporarily and safely). Also, if the thing can idle indefinitely without chugging and dying then there's obviously a dynamic issue involved.