ongoing loss of power

[yaris9876]

In the last few weeks I have had a dramatic loss of power on acceleration sometimes helped by releasing and pressing the pedal a few times. If it is compression on this high(405K) miles engine why did it come on suddenley and why dont I burn any oil?
I have cleaned throttle and air filter assembly completely. Cleaned OCV and that fixed an idle problem mostly...the OCV needs cleaning every 20K I think.
I replaced the entire fuel pump,filter,regulator assembly with a used low miles unit that works good. No problem putting it in. I replaced injectors with rebuilt ones from Injector Warehouse in South Carolina. No leaks.
The engine light blinks frequently but not all the time. I get codes 301 and 011 but not all the time and I have had codes for years and not had any real problems. They mostly come from the OCV problems on the 07. That valve just gets grimed up and doesnt work right
unless you clean it all the time.
I think its either the pedal wires are bad or compression but like I said I dont burn oil.
I dont want to diagnose too much more because of the money pit.....
If I take it to Toyota will their diag. machine tell more than my Scan Gauge???
Will they know if the pedal is not communicating correctly???
If its compression then I will ditch the car or engine but I dont think its that.
Does anyone know what might cause that lack of power on acceleration like that??
Sometimes the power kicks in suddenly but its happening less and less.
I am stumped....

[Viperoni]

It could be an intermittent problem with the sensors on the gas pedal, but it should throw a code....

FWIW, my compression readings are 190, 195, 110, 190, and I burn around 1L every 1k miles, no blue out of the exhaust. It wouldn't be intermittent like you're getting though, I only noticed a slightly different exhaust note and the engine sounds more "knocky" (piston slap).

[JustPassinThru]

Have you switched grades or sources of gasoline? If you have a batch of rotgut, and it starts knocking, there may be an automatic spark retarder.

I don't know that there is. I know very little about how these are set up; but many distributor-free high-performance engines do this today.

[frog13]

Just a WAG (wild ass guess) on my part. Have the valves been adjusted?. Cleaned the MAF sensor?. There is also a "sensor" that regulates fuel supply. Meaning : When you let off of the accelerator the fuel supply stops briefly (it is designed this way,fuel economy I suppose?) and perhaps the silly thing needs cleaned or replaced?. Again just a guess.

[yaris9876]

Toyota dealer says needs 1 coil and new gasket for oil leak on valve cover. Oil can get in and clog the coils. They want 210 for labor only.. Is that reasonable?????? I dont want to do it cause they might notice other stuff under that I would miss.

[JustPassinThru]

I wouldn't say it's reasonable; but it sounds like it falls under "controlled ripoff." I haven't seen egregious fraud at a Toyota dealer - and from my experience, they've had plenty of chances with my own mother. On the contrary, they did her (one dealer) and me (four dealers in three states) right.

These things are complicated. Unless you personally know the guy who'll do the work, know that he knows these cars...I'd stay away from independent shops. Some are very good...but you pays your money and takes your choice. And an independent may not even be crooked; just doesn't know the details of these setups.

[Viperoni]

I wouldn't say it's reasonable; but it sounds like it falls under "controlled ripoff." I haven't seen egregious fraud at a Toyota dealer - and from my experience, they've had plenty of chances with my own mother. On the contrary, they did her (one dealer) and me (four dealers in three states) right.

These things are complicated. Unless you personally know the guy who'll do the work, know that he knows these cars...I'd stay away from independent shops. Some are very good...but you pays your money and takes your choice. And an independent may not even be crooked; just doesn't know the details of these setups.

Valve cover gaskets on these cars are a cinch and should be done in less than an hour.
The ignition coil needs to be removed at the same time.


An intermittently faulty ignition coil can definietely cause the problem you're getting.

Does the exhaust note sound any different when the car's experiencing it's lack of power, or does the engine shudder?

[yaris9876]

yes,one coil can screw all the other coils.
anyway paid the extra $ and got a new coil and gasket and probably some adj. on their scope..
the rig runs perfect again with full power and no codes. But I know I will get codes again after awhile.
The OCV on these 07 will always screw up after a while.
I need someone to do a full pictorial of a clutch swap. I know mine must be getting worn.

["G"]

ocv?