2007 prius high rev, low gear on long drive

102k Miles... original owner.,

1. On 30+ minute drives avg 80+ mph with hard acc now and then... I've noticed that my prius sounds like its in a lower gear - sounds more like it would be in B, or when its revving higher to warm up on a very cold day.

2. Once its in this high rev mode... and I keep driving., I've also had it do this weird thing where just around 80mpg it will disengage acceleration, and cycle it back on., (accelerator is pressed), causing it to jerk back and forth...

3. on very cold days (2-10 deg), its usually reving high., and it does not need the 30 minutes to get to point 2 above..

4. it first started doing this around 60k miles., but my drives are usually 20 minutes long., and with no check engine light on.. .didnt want to deal with it.

5. If I park it for a few minutes (off) and/or turn back on and reverse and drive off., its back to normal....

Hoping that it was something covered by the emissions warranty, I took it in for diagnostic - they claim that the only thing that showed up was error codes for cylinder misfire and that i need new coil and sparks., quoted $950... I can change this myself.

They also claimed water pump has a leak (this was replaced in 2010 as part of a recall), they quoted $550... I can change this myself., but it requires a bit more work.,

They also wanted new brakes and rotors (front)., quoted $560

they also wanted to clean the back breaks., quoted $130.

Diagnostic cost is $120....

I can see how cylinder misfire can cause the jerking... I don't understand how it can cause the high rev - this seems more like a temp sensor or engine control issue..

I've run into some early 2008 posts for 2007 prius's where people had it in B by mistake., and that was the issue for the high rev - Some were just new to the prius and found the acceleration to be different so those didnt help me much in a search for answers...

anyone have suggestions on what to look at., or what to ask the dealer to do?
p.s. main hybrid batter and some fan components where changed at 82k when battery failed.

 

Thanks!

Going to order Denso 6731306 and (i think) denso 3324 SK16R11 Iridium plugs, amzn has coil at about $56 each and $7.60 per plug prime shipping.

I asked the dealer to show me the leak - the tech asked me "have you been hearing a running water type of noise"... and yes.. I had been, but I thought it was the heavy rain and melted snow swirling around somewhere under the body... turns out that majority of the coolant had indeed leaked out.. and that was the remaining bit swirling around in there.... so. It's getting a new engine water pump + belt.

Since I was now talking to tech directly, I told him about the high rev - he said no one told him about the high rev - just the engine on/off at 80+ speed and that lead to them checking the coil and sparks and at least 1 registered misfire while attached to computer - so his take on the high rev is the "not enough coolant" causing the temp sensor to not read things correctly and causing the high rev - he said it could be this, but he's just guessing at this point.

Ran into these two videos for the throttle body and MAF

seems easy enough., will add the sprays to the cart or will get them at a local store.

Impressive list of Prius's on there - Do you suggest something other than the Denso part #'s I'm looking at getting?

 

Will do - Ordering those now... its been many years since i changed sparks on any car (10+)... looks like people still recommend anti-seize... will order a tube of that too..

 

Just got the prius back with its replaced engine water pump, serpentine belt and new front breaks + rotors. The sparks came in yesterday as well, if it warms up a bit, I'll change them today.

Should probably start a new thread for this question - After letting go of the accelerator, I'm noticing a decent slowdown/deceleration. Letting go of the accelerator (below 30 mpg) on a flat road would give good roll without a big drop in speed, slight press on accelerator would give all electric speed gain back towards 30mpg...

Now, on a flat road with foot off accelerator, you get a mile drop per second or so, and even the slight press wont give it back its speed gain... I did fine another thread on a belt replacement and to quote you "deflection of a new belt should be between 0.35 to 0.47 inches. A usedbelt should show deflection from 0.43 to 0.59 inches".

I'm going to guess that the slowdown is from the new belt and its normal, as it gets some wear it will give a bit? Just wondering if I should go back and have them adjust to correct tension.

 

Thank you - Yes - mph and i did not check to see if it is in spec.

I took it back out on the highway to test it out more - and yes it probably is the front brakes. re mpG - I noticed that I have to accelerate more and the mpg drops into the low 20's to stay in the 75+ mph range. I'll probably take it back to them first thing in the morning.

I ordered the OE plugs through my friend back in CA and he included coils - so since I had them off, I swapped out the coils as well. I used 13 ft lbs for the plugs and 6.6 ft lbs for the coils and I have my fingers crossed that I none of these are defective as I really dont want to open this up again; I've got a back injury that makes working on this more tiring than it should.

This might also be a good time to just buy a ODB2 scanner and connect it for the next 30+ mile drive to see what codes show up - I've never had a check engine light though. so onto looking for existing threads on ODB2 suggestions