hesitation on acceleration even on a new battery

Where did you get the battery? is it truly new from the Toyota factory?

Have you got any diagnostic tools like techstream, dr. prius, torque etc?

 

sounds like an engine problem. if you're at two bars, the battery isn't supplying much power.

how many miles/km on her? have you cleaned the throttle body? egr circuit?

 

I don't think that is true at all.
The amount of power the battery supplies should not vary enough so so that you can tell the difference.

I'm not sure that a slight hesitation is not "normal" when "jumping on it" to get sudden acceleration.

I agree that it might be a gas engine problem.......if there really IS a problem.

Note: It is generally accepted that ACCELERATING is NOT a good way to get yourself out of trouble in any traffic situation.
But then things might be different where you live.

 

Is the coolant level for the engine stable?

 

It seems to me when it's down to two bars it's "slightly" sluggish during acceleration. I'd suspect it's the car's programming, being more protective of what charge is left.

 

Some additional questions:

• How many miles on your Prius?
• Egr circuit cleanse complete?
• Plugs changed?
• Throttle body and map sensor have been cleaned / inspected?
• Any dash lights?
• How’s the fuel pressure / delivery?

Hesitation is caused by 2 main factors : air or fuel so that’s where I’d focus if the coolant level is stable and the head gasket isn’t compromised.

 

Air filter......fuel filter........?
Vacuum or intake manifold leak ??

There haven't been any modifications to the intake or exhaust, has there ??

A healthy dose (or two) of a good fuel system cleaner might help some too.
(Seafoam is NOT a really good cleaner.)

BUT you have a fairly old car with a LOT of miles and some small performance loss is probably to be expected.
How's the oil usage ?

IF.....something is causing it to run a bit more lean than normal, when it gets really HOT it will get even leaner.

And finally, is the fuel you are using considered "premium" high octane where you live ?
If so, try going back to "regular" grade, which is all the Prius ever needs.

 

How much ?
Engine wear also causes loss of performance when it gets bad enough.

Read my last post again. Some edits have been added.

 

What would that be a symptom of, excessive carbon in combustion chamber?

More evidence, maybe carbonned up piston rings causing high oil consumption? Can you quantify that oil consumption: how much oil consumed per say 1000 kms?

Things to try:

1. Use an inspection camera, see what the combustion chambers look like. Look for carbon, also evidence of coolant, and just a marked difference between the cylinders.

2. Maybe worthwhile to remove the pistons and pour a couple of ounces of carbon-busting solvent in each cylinder (aforementioned SeaFoam?), let it sit for at least a day, then manually crank the engine a few times, baste out any solvent that remains abouve the pistons, reinstall plugs/coils, drain and replace oil.

3. Compression test?

4. Leak-down test?

 

What about the spark plugs?

Like most cars, a Prius cannot determine its own fuel pressure. To test, you must temporarily install a pressure gauge on the fuel line and then run the pump to take a reading.

 

agree with mendel. if it is too hot, car goes into battery protection mode. can you hear the cooling fan running? have you cleaned it?