Fluctuating Idle

Hi Guys,

I recently bought my first used Tacoma a few weeks back. First post for me, but looks like lots of real helpful people on this forum!

Anyhow,

Truck is 97k miles old, I had the shop replace the timing belt, front rotors, and add more coolant. I notice that when I am in drive, but stopped at a light the RPMs tend to *sometimes* fluctuate between 500 - 750 RPMS. It doesn't happen all the time, its very hot here in texas, and I am running the AC.

Is this type of fluctuating normal? Should I take it back into the shop to get the issue resolved? Thanks in advanced everyone.

 

turn off the ac and it wont do that. the compressor kicks in and the engine compensates by raising the rpm a bit or something like that?

 

Yeah that's completely normal. Your a/c unit uses electricity that comes from your battery which is charged by your alternator so it's just the engine running the alternator a bit harder to compensate for the power draw.

 

I believe you are correct. 250 RPM fluctuation to compensate for the A/C compressor is nothing to be concerned about, perfectly normal.

 

Is it normal to sit around 500 - 750? Would normal be more like 0 - 250? My knowledge of RPMs is pretty bad. I appreciate all this help!

 

0 means your engine isnt running. your idle shoule be around 5-800ish

 

0 means the engine is not running. 500 - 750 is fine at idle, 250 would be too low and would probably start spuddering. RPM is Revolutions per Minute, 0 revs means the engine isn't turning.

 

try changing the fuel filter