Engine RPM Issues

[euser]

Well to start, I have a 2002 Limited 4Runner with around 212,000 miles. I have an issue where my engine RPM will randomly droop and lose power. When idling it may shut off and need to be restarted, when driving it will droop to around the 400 mark then spool back up to normal. It lasts maybe a second or two max. I first experienced it last summer, and then it went away. It came back today. It seems to be correlated with very high ambient air temperature. Today it hit around 110, and the last time it happened was during the high heat of last summer. I don't remember ever experiencing it at temperatures below 100 degrees, and its not a regular occurrence. Sometimes it happens, sometimes it doesn't. It also only happens after its been running for a while. It never does it on my short 2-3 mile drive to work if it starts cold. I completed a 2,400 mile trip in may and didn't have this issue until I got back to Vegas.

Any ideas what could be causing this? Could it be an air intake issue with high density altitude or heat? Although I know 4Runners operate at much higher altitudes than it would be experiencing through DA. It has always started back up on the few instances it shut off, and it drives normally once the RPM moves up to normal. Also, occasionally I'll smell a gasoline smell after an extended drive when I exit the vehicle (never inside it), however I can never see it leaking gas along the lines/tank. It'll make a suctioning sound that is audible on the gas cap, but I got a new gas cap last year so it shouldn't be bad.

 

[StreetCreeper]

Well to start, I have a 2002 Limited 4Runner with around 212,000 miles. I have an issue where my engine RPM will randomly droop and lose power. When idling it may shut off and need to be restarted, when driving it will droop to around the 400 mark then spool back up to normal. It lasts maybe a second or two max. I first experienced it last summer, and then it went away. It came back today. It seems to be correlated with very high ambient air temperature. Today it hit around 110, and the last time it happened was during the high heat of last summer. I don't remember ever experiencing it at temperatures below 100 degrees, and its not a regular occurrence. Sometimes it happens, sometimes it doesn't. It also only happens after its been running for a while. It never does it on my short 2-3 mile drive to work if it starts cold. I completed a 2,400 mile trip in may and didn't have this issue until I got back to Vegas.

Any ideas what could be causing this? Could it be an air intake issue with high density altitude or heat? Although I know 4Runners operate at much higher altitudes than it would be experiencing through DA. It has always started back up on the few instances it shut off, and it drives normally once the RPM moves up to normal. Also, occasionally I'll smell a gasoline smell after an extended drive when I exit the vehicle (never inside it), however I can never see it leaking gas along the lines/tank. It'll make a suctioning sound that is audible on the gas cap, but I got a new gas cap last year so it shouldn't be bad.

My truck has been known to do the same thing in very similar circumstances as yours. Im too stoned right now to recall what conclusion I ultimately came to about it -- however, I never bothered to fix it as it doesn't happen very often, and when it does, as you mentioned -- it always fires right back up.

**Edit** Ok if I recall correctly now, the general consensus was a dirty IAC valve or something along those lines. I of course didn't clean it ... because I'm lazy ... and my truck runs good anyways. But I guess if I was in Las Vegas heat all the time, it might become a bit of a higher priority.

 

[Buckaroo]

Any ideas what could be causing this?

Regarding problems with idle,would suggest you remove and clean the Idle Air Controller (IAC). While you are in there, clean the Throttle Body (TB) as well.

Suction sound when you open the gas cap is normal.....

Buckaroo

 

[euser]

Regarding problems with idle,would suggest you remove and clean the Idle Air Controller (IAC). While you are in there, clean the Throttle Body (TB) as well.

Suction sound when you open the gas cap is normal.....

Buckaroo

I've tried cleaning all of that as well as the MAF. Also, the sound and smell from the gas cap is while its sitting after a longer drive, not when I open it.