4.7L VVT-i sluggish

[Htown4runner]

I have a 2005 V8 Runner and I have noticed something interesting over the past couple days. I live in Texas so it has been getting REALLY hot here... 95+ and whenever I drive my 4runner when it is that hot it feels really sluggish. The engine sounds louder like its working harder and I feel like it doesnt accelerate as quickly. Has anyone had any problems with this or noticed the same thing recently since summer is starting up. If no one has any input I guess ill take it to the dealer and see whats wrong. Thanks.

Ross

 

[beeper]

My ride is a 2005 V6...I don't know what your problem is but gas could have something to do with it. Maybe try premium or another station instead of your usual. Just a thought...sometimes its the simplest things.

 

[TeCKis300]

Most any car will run more sluggish on a hotter day. Has to do with the air being less dense. Also, your A/C is probably being used now....are you comparing to when you don't have the A/C on? Lastly, you may want to take beepers advice on using premium fuel during hot weather. Detonation is much more likely during hotter weather and the car may be detonating and the ECU is pulling lots of timing which would make it seem more sluggish. Does the noise you talk of sound like rattling marbles? Then it is definitely detonating/pinging. Use that higher octane gas asap.

 

[Htown4runner]

I do use premium gas, but the best we get here in Lubbock is 91. I did compare it with A/C on and off but I didnt notice a difference. It doesnt sound like marbles at all, it just sounds really loud like the fans are working harder or something. For example, when you turn your car on in the mornings and first drive away, have you ever noticed that your 4runner is somewhat louder than it usually is? Once it warms up it goes away and is normal. Its like mine keeps sounding like is does when it first starts up when its really hot outside. Tonight it was about 80 and I didnt notice the noise it at all. Im thinking its climate induced, but I was going to see if anyone else has the same case.

 

[alpha]

hmmph, it's been 80s lately, will be tomorrow too.. i think it hit low 90s today.. didn't notice anything when i was moving cars around, but that was short distance too.. but i drove my dad's today.. and i didn't notice it being louder than usual.. but i haven't really paying attention to if it was louder.. if it was, it would have been slight.. but it didn't feel sluggish.. i'll see tomorrow how mine is..

but i have the v6.. but either way, if it would be sluggish, then......

 

[02sport]

not sure on the v8, but probably your fan clutch engaging to draw in more air flow. normal

 

[Htown4runner]

thats what im thinking. This morning on the way to work it was 85 and i didnt notice it. We'll see around lunch time ill be sure to post again.

 

[05V8SPRT]

I have not used m7 05 V8 yet in the heat. However, 2 things you need to consider:

1. Hot Air = less HP, the hotter the less responsive

2. Some people are MORE sensitive to changes in HP due to climate change than others....

Just so happens I ran 87 octane in my 05 for the first 25 tanks or so. Figuring it was BS that 93 would produce more HP. Well, now I run 93... I can REALLY feel the difference and the engine runs smoother.

AC on + 90+F = about 30+ less HP at the crank

 

[Htown4runner]

it was 103 yesterday and it did it again... later that night it was 80 and it wasnt doing it. I think it has something to do with fans, at least thats what it sounds like.

 

[independent70]

come on guys... complaining over 90s and 100???? haha i love in new delhi and its 40(104)-49(120) degrees celsius here... today was 46.. it is sooo hot.. and its true cars/suvs run slower on hot days and what a lot of the buses here do is remove the radiator guard and add extra fans that run of battery vs engine...

 

[MicaBlue03]

Noise is very likely the fan clutch

The clutch is a fluid-filled assembly and the coupling is engaged when you start up, and for the first 15 seconds or so. Then, if the air gets hot enough it re-engages and will make the engine sound louder. It's normal.

It does make sense that you get less HP at higher temperatures, but if you're using 91+ octane fuel I'm slightly surprised that you feel such a big drop when it gets hot. On the off chance that your filling station is cheating you on the octane, it might make sense to try a different one. Just my two cents.