1st Gen. RPM Flucuation when Idle. Not A/C related and not stalling. Help?

Hello,
I have a 2004 Tacoma 3.4L M/T. I looked at other threads for this similar problem but every thread I saw seems to be slightly different. Sometimes when driving (not all of the time and usually not when I first start up the truck), the RPM's begin fluctuating between 1000-500 ONLY when idling. There is never any flucating when giving the car gas, the car never has stalls (although a couple times it felt like it may). This will happen when the A/C is on or off.

I pulled the MAF Sensor and cleaned it, and it didn't seem to make a difference. If anyone has any ideas or a link to another thread I may have missed I would appreciate it.

 

Do you have the electronic or mechanical throttle body?

 

04 will be electronic

 

Could it be something to do with the Idle Control Valve? I'm not sure how to check that for issue.

 

If you have the electronic throttle body I don't believe it has an idle air control valve.
Do you have an engine light on?
Any codes?

 

I keep getting a small EVAP system leak (p0442 I think) but I think that's just a problem with the gas cap..I currently have a check engine light so I will read the code and see if it's the same or something different when I get home.

 

Wouldn't hurt to check all of your vacuum lines.

 

Allright will do..I'll run the code and check the lines...is a visual inspection usually efficient or is it best to check by spraying starter ether?

 

welcome to my world the past 7 years. I've had it stall a few times when just touching the gas and letting it off. had a multi-crank issue a few times (like 8-10 cranks)

never any codes for the idle (codes for other things sometimes). I've just dealt with it and figure if it still runs and doesn't cost me anything I don't want to throw money at random parts

 

Just ran the codes, it was P0442. Checked all vacuum hoses and didn't see anything loose. When I get a chance I will check with starting fluid.

Thats too bad to hear that you haven't been able to find the solution to the problem. Right now for me it is just a bother. I am worried if it gets worse hill starting will be hard at low rpms. If it gets to the point of it stalling when idling I will throw parts at it.

If an MAF sensor failed it would give a code? Appreciate the help and any ideas.

 

Update for anyone who is interested:
I took it to a shop bc it made my truck stall. They said it was simply carbon built up in the fuel injectors and throttle body. They also changed out my spark plugs. I have not had the issue since. Before bringing it to the shop I had ran some Lucas in my gas but I may have been too far gone. Hopefully this helps someone.

 

Thank you for checking back in with the update.

Always helps with future researchers.