What is your question?
I have a used 2009 Toyota Matrix. My car started to lose power while driving on a highway. It always happens on the same spot when going over an overpass where it's a short uphill. I'm on a cruise at 65mph. When the car reaches the top of the short incline, it starts to lose power down to around 40mph. So I pull over.
The vibration of the engine is very noticeable. The sound is irregular ramble like an old classic car. To me, it sounds like a misfiring. Prior to this happening, there was a check engine light for a loose fuel cap. It came and go but recently has not gone away even though I had replaced the fuel cap. Today, it happened at a different place. It happened on an incline but where it dips down to go under an overpass. I noticed the ramble when the car started the decent and started losing power when it began ascending.
The car has also been showing the same vibration/ramble after driving on a highway. I notice when stopping at a light or stop sign.
Please help.
What makes this problem better or worse?
Worse - More than 10 min of high drive and uphill. Better - Turning engine off/resting.
How long has your 2009 Toyota Matrix had this problem?
About a month. Frequency of the issue is increasing. (Every day at the same spot for a week and a half)
I purchased a scanner and it lists 2 codes: P0352 P0456
P0456 is an evaporative emissions system issue that may not be due to a loose fuel cap. It is due to a small leak, which may be the cap, but may be something else. P0352 is a malfunction with an ignition coil that requires testing. This is the one that is related to the running concern you speak of and requires hands on testing.