99 rav 4 cold start

toyota
start
rav4

#1

I have a transient starting issue with my 99 rav 4

Sometimes when I start it (only when it’s been sitting for more that 3 hours) the engine idles really low (between 100 and 200 rpm) or wont idle at all and stalls. After the engine warms up some the symptom goes away.


#2

Any check engine light on? Coolant temp sensor, vacuum leak, idle air control valve?


#3

I replaced the plugs, fuel filter and air filter today and the check engine light came on for about 4 minutes. I couldn’t tell you about coolant temp sensors although the the fan turns on and off automatically and the heat works fine. As for vacuum leaks … I would suspect it to run rough more consistently although that is just my shade tree guess. I just spoke to the dealing about a new idle control valve … $285 clams so I think i’ll be trying that option last although I have a feeling that will do the job.


#4

Has the throttle body been cleaned recently? If not, have that done with emphasis on the Idle Air Control valve and passages. It is possible that the IAC is getting stuck in the warm run position and not openning to allow a good idle when cold.

Hope this helps.


#5

thanks i’ll give it a shot


#6

The temp sensor is one of the things that “reads” the engine is cold and increases the gas in the air-fuel ratio to make it idle faster, I think it can be checked with ohm meter. Others may know for sure but I think you test it, say its 80 out then put in the fridge and retest and reading will go dn or up but not sure what readings should be. Use search.
I would Clean throttlebody and idle air control valve first. Spray IAC with cleaner while unplugging and plugging it back in a time or to.