...I have a problem that I cannot put my finger on.

When driving down the freeway it feels like I'm driving into a head wind. I'm driving 70 mph but it feels like the car is working harder to drive in spurts. The RPM's stay at an even 2K and the speedometer doesn't fluctuate.

Anyone have an idea as to what the problem could be?

FYI...'05 TL with 103K miles

 

I should make it known that my beautiful wife, god bless her...put 87 octane in my tank about 600 miles ago. I added some fuel system cleaner the tank after that along with resuming my use of 91 octane.

 

air filter?

 

I had a similar problem and in my case replacing the egr valve solved it.

 

Just curious is it really hot right now for you? It 'may' be the battery, as some people have reported, where in the heat the battery would bog everything down, but getting a new better one solved all the problems.

 

Any lights? Cel?

 

It's been in the high 80's, low 90's....

 

I have noticed after owning the TL for last 4 years in temperatures ranging from 85+ plus humidity maybe. The engine does get pretty weak plus not to mention the combination of the gear ratio in the 5AT plus the weakness in the automatics in these cars. I have owned an 05 Accord before the TL and it was a 4cyl 5AT and that car didn't feel too bad in hot weather even with temps being 105 with heat index in 115-120. Even a 1999 Corolla 4AT felt more responsive. It seems like the TL's by default in stop and go traffic really bogs down especially in 85+ temps

 

If it was the air filter, it would have to be pretty significantly clogged to cause any performance issues. A stuck open EGR would result in the car running poorly and being hard to start, and I would expect a CEL. One thing you don't want to do is just start replacing parts randomly without cause. As for the tank of 87 octane fuel, I really doubt that would have caused a long standing performance issue.

Some easy/ cheap stuff to do would be to clean the throttle body with TB cleaner, clean the EGR, replace the air filter (cheap to do) if it needs it, and disconnect the battery, resetting the ECU (just make sure you have the radio and Nav codes if you have a Navi equipped car). The spark plugs are about due to be replaced but in truth, with a high energy ignition like cars have these days, the plugs should still be good.

Having the battery tested is a good idea as well.

If it starts and idles well, it's probably nothing too serious.

 

an additional point to be made:
the ECU might pull timing with 87 octane, combine that with the heat and these cars suck!!!

 

Nope

 

I'm trying not to make any assumptions from your screen name, but if you are like me, the older and heavier we get, the slower we are. I'm personally pushing 3/4 million miles on my fat ass. I'm just not as speedy as I used to be...

No, but really, you need a diet, er-um, tune-up.

 

There's the problem. Detonation caused by 87 octane causes retarded timing. The ECU senses the pinging and retards timing but constantly tries to put full timing back in since retatded timing hurts power and mph. What you experience is an overall loss of power with some surging as timing is advanced and retarded over and over. Even though you filled up with 91 octane afterward you had at a minimum 3 gallons of 87 in the tank still even with the light on and zero miles to empty. It should be normal by the second full up of 91.

It can't be the air filter. If its so plugged that the engine has trouble producing the 35hp required to maintain freeway speed it would hardly accelerate at all with the 80+hp required to accelerate normally from a stop. If it were a restriction going down the freeway steady state it would be limited to about 35hp even at full throttle.

 

I reset the ECU this afternoon before a one hour freeway trip and the problem seems to be gone now. Would resetting the ECU help with this issue or am I taking crazy pills?

 

Actually, it makes perfect sense. When I posted, I didn't think the ECU would store retarded timing settings (I thought it was a dynamic process) but as IHC indicated, the tank of 87 persistently retarded the timing. Glad all is well now.

Make sure the Mrs. uses 91 gas from now on.