Engine lack of power?

It;s doing it again.. Has to be a sensor? Still no codes with obd2 scanner.

Usually a sensor will set a code, so I'm a bit confused. When you place it in neutral you said it smoothed out. Is that correct? Also, I read back a couple posts. Please be careful increasing fuse amperage. You don't need a fire.

I have done a bunch of research and the only thing I can find related to 10 flashes is a p0137 which is related to an oxygen sensor. And I'm not confident the code is accurate.

By any chance, can you get your hands on a live data scanner?

Let me know.
Joe

So tonight I started it let it warm up for 10-15 minutes. She drove wonderful. Went inside for about 7 minutes for back in and rpm's were low started chugging almost shutting off. On way home I would almost floor it and there was no power no get up. Took forever for it to get to 40. Then when is slow down almost to a stop it would want to shut off. Finally get home. And just like that it has got power and the snappiness back.. What is going on?? Still no codes.
Tomorrow I might bring it to O'Riely's or AutoZone see if they can't run a diagnostic test on it. I feel defeated!

With cruise control engaged at 55 to 60 mph, the tach reading 1500 rmps, the engine rpms will fluxate from 1500 to 2000 rmps while traveling down the road.

Does the truck accellerate when this happens?

Every time this happens I forget to put it in neutral! Tomorrow is another day with this truck. Starting to think it hates me, lol.

[quote:85d94e681a="Jacobandnickolas"]Does the truck accellerate when this happens?[/quote:85d94e681a]

No the engine rpms increase.

I have to be honest, that sounds like either a plugged converter, weak fuel pump, or something restricting air into the throttle body. Tell me, is there any smoke from the exhaust when this happens. Also, is there any noise coming from the exhaust when it happens.

Joe

I hae to say it, but if the rpm's are increasing and the truck isn't gaining speed, it sounds like the trans is slipping. Has it ever done this without the cruise control engaged?

I picked up a MAP sensor today and will be installing it soon. Now you mention the catalytic converter. Do you know what the temperature is suppose to be before the catalytic converter and after the catalytic converter using a heat gun? And the noise or smoke I'm not totally sure. I will fire it up and take a look.

Could the shift solenoids be going out in the trans. also now the eng. rmps is fluxating wth the cruise off, running about 60mph, truck now acts like the torque converter is trying to lock up when stopping.

The converter internally can reach temps of over 1200°F. When checking it with a infrared gauge, you should see differences under 100°F between the inlet and outlet. The outlet being hotter. (Note the engine should be at operating temp) If you see temps exceeding approximately 200°F, that is usually a good indicator the engine is running rich (too much fuel). If the difference is over 500°F, it usually indicates there is unburned fuel making its way to the converter.

Now, if you suspect there could be an issue with the converter being plugged, you can check back pressure by attaching a pressure gauge to the exhaust system. Most times, I remove an O2 sensor (Pre catalytic converter) and connect there. At an idle, back pressure should be no higher than approximately 4 psi. If you find it to exceed 7 or 8 psi, something is blocked.

Also, you can remove an o2 sensor and see if it runs better. That will allow added release of pressure. It won't release enough to make things perfect, but you should notice a difference. However, it will turn the check engine light on indicating an O2 sensor problem.

Let me know if you do either of these tests and the results.

Take care and try to have a good weekend.
Joe

Wow! This is an interesting one. Again, if the RPM's increase with no speed or accelleration from the engine, I feel the trans is slipping. The shift solenoids only shift the vehicle from one gear to another.

Hey, how I will be hooking up an onboard scanner. What am I looking for? Any help would be great. The truck doesn't have a manual. So any help would be fantastic. Thank you

If the trans was slipping should i not get when i accelerate from a stop. i am thinking that since everthing is run off the pcm that i might be getting a false signal from the electrical side of this problem.

I also used an infrared thermometer at checked the cat. After the cat going towards rear is 230 the cat 141 and going towards motor is 276....

One would think so; however, if the RPM's increase, there should be an accelleration.

And yes when I put it in neutral it smooths out a little. Tail pipe makes a Blurp Blurp kinda. Light white grey smoke... Keep in mind if I'm driving put it in neutral and restart it everything is fine.

The temp of the converter itself is odd. Do me a favor, remove the oxygen sensor and see if it makes a difference.

As far as the temps, the converter itself should have been hotter. Also, yours is hotter before the cat. That shouldn't be. Try removing the )2 sensor and see if it makes a difference.

Joe

Would the temperatures be off because I don't have a muffler? It was rotted so I cut it off and went with straight pipe.

But, I'm going to be doing them sensors later today and will get back to you. Starting to wonder if it's not the PCM itself. D oh sent make sense. Been testing and it seems as if I start it shut it off and start it again and it runs like it should.

Anything is possible. When you turn the key off, it could be resetting things. I just want to recap. You checked fuel pressure, codes, and wiring for grounds and power supplies, correct?

Joe

Yes, it seems as if it resets itself after restart. Yes on fuel pressure. Yes on codes. Yes on grounds. I'm a little rusty with the power supplies. That area I really don't know anything.

The one thing that I can think of that under the right conditions won't set a code, but it can cause driveability issues is the crank sensor. Have you done anything with that? Take a look through these two links and let me know if anything seems to mirror what you are experiencing:

https://www.2carpros.com/articles/how-a-crank-shaft-angle-sensor-works

https://www.2carpros.com/articles/symptoms-of-a-bad-crankshaft-sensor

Joe

Yes it idles high when cold. Sometimes you got hold key until it finally fires. It'll crank but not always fire up. Intermittent stalling yes. Sounds to me I might need a crankshaft sensor..... I'll see if parts store has one. Fingers crossed.

Yes it idles high when cold. Sometimes you got hold key til it finally fires. It'll crank but not always fire up. Intermittion stalling yes. Sounds to me I might need a crankshaft sensor..... Wait I already replaced the crankshaft position sensor. That was the very first thing I dif

You mentioned that you were getting a live data scanner. Do me a favor, check the coolant temperature sensor reading, let me know the short term fuel trims, and if you haven't, (and I think you did) reconfirm there are no vacuum leaks.

I am starting to question if there is a problem with the idle air control valve. Most can be serviced, but this one can't.

The info from the live data scanner may be very helpful. We spoke about it a few posts back but then stopped.

Let me know.
Joe