losing power at high speeds

Well previously I have had the cruise control kick off while going up hill, but I just assumed that it was because there wasn't enough power. But now it won't kick on at all

 

Sounds like its leading back to TPS problem then. Clearly an electrical problem if CC won't come on at all.

 

My guess is two separate problems.

Like @Hondah suggests, a converter, or even a muffler, beginning to fail/clog the exhaust stream would create power loss, until it clears itself. Potato up the tailpipe as it were.

Eventually the converter should set a code, but thats not helpful if it quits running first. I've had one fail so completely it would not start due to the backpressure.

In the olden days, I would have also suggested a fuel filter clog, which is typically a high speed revelation when it starts to fail. I still wouldn't rule that out, but it would take a pressure test to prove a problem worthy of digging into the tank.

If your cruise uses vacuum to hold the throttle position (easy to determine with a look under hood) the lines to the diaphragm should be easy enough to check. Split ends might be remedied by trimming and reattaching. However, vacuum leaks usually reveal themselves when the engine is under high/highest vacuum, as when at idle. No idle issues mentioned.

There is a switch above your brake (and clutch if manual) that disengages cruise when the pedal is used. If the switch is out of contact, adjustment, or broken, it will not allow the cruise to work.

 

thank you much. I will have a look at that

 

^^^^^^^^^This^^^^^^^^^

 

Is it just a button?

 

No its the brake switch itself mounted up on the brake pedal. Controls brake lights, cruise control, torque converter lock up, and will throttle down input from gas pedal if brake is applied. May have to check switch for proper operation and proper adjustment. Should activate with a slight depress of brake pedal.

 

Just noticed your a manual. Same somewhat applies to clutch switch.

 

Well driving back from work cruise control worked and no loss of power at all. Maybe some how that activated today.

 

I agree with the others there are only a few things that will effect both of your symptoms.

Brake switch and clutch switch ( for a manual transmission ).

 

Check your Brake Switch I was having a problem with my accelerator cutting out just like your symptoms
I re-adjusted the switch which is very easy and my problem solved.

 

If the engine power is being cut when your accelerator position is about 1/2 way down or more, and you're not getting any codes or CEL - check the brake activation switch on the brake pedal.

When your ECU thinks the brakes are being depressed while applying the throttle past a certain threshold, the ECU will cut engine power. This was part of the 'fix' to the unintended acceleration issues several years back.

If your brake activation switch (or clutch switch on a manual transmission) is not adjusted correctly, or faulty, you may experience these symptoms.

To check, give the switch behind the brake pedal about 1/4 turn counter-clockwise to loosen it. Press and release the button on top of the switch to make sure the brake lights turn on and off correctly. If the switch appears to work correctly - check the adjustment on it; Make sure the brake pedal is all the way up, then push the switch all the way in, and give it about 1/4 turn clockwise to lock it in place. You'll notice the switch pulls away from the pedal slightly after you tighten it. That gives it the correct gap.

 

If he didn’t get it figured out in the past 4 years.......there’s no hope. Lol

 

True for the OP. However, it'll help others moving forward

 

I'm having a similar issue now. Random loss in power while cruising on freeway. Truck kinda stalls no matter how much throttle input. Resets it self usually after letting off the pedal and or going down a gear. Will check this tomorrow. Thanks!

 

Did you ever find the issue?

 

Was this issue solved with adjustment/ new switch.?

 

The problem was never fixed, as I moved abroad. If you have solved, the issue please let me know.

 

My issue was solved wi an adjustment of the brake pedal switch. No problems since. I did order a new switch just in case this one totally fails.

 

I’m having this same issue as well. My 08 TRD sport 6 speed manual will randomly start jumping while running at highway speeds and I have to let out of it and then get back on it and it’ll clear up most of the time. I have since cut all the cats off it and put a Borla straight pipe exhaust system on it and so far the issue has disappeared but I’m also looking into crankshaft positioning sensor replacement and timing chain upgrade along with cam shaft positioning sensors replacement. But it could more than likely be stopped up catalytic converters because like I said mine hasn’t done it since. Just make sure to weld your O2 sensor back in whatever you put back on it