Hard Starts

[99Black4R]

My 99 4Runner (3.4 L) seems to start really well when it the engine has been off over night or off for a couple of hours. When the engine is cold, I turn the key and bam, it starts before the crank turns a full revolution. But starts after the engine is warmed up (normal operating temp.) is a real weak start. Almost stalls before the engine comes up to idle. The starter turns the engine over good so i don't think it's a battery problem. The truck runs fine with no hesitations or misses. Has anybody experienced this with their 4Runner? Any advive?

Thanks

 

[NoDak]

i think i know what is happening. on my 98 runner, my idle after warming up was sitting around 500-600 rpm, on the verge of dying.
the idle rpm if i remember is non user adjustable (someone correct me if im wrong on this). this is somewhat related to your problem i think

these are ordered by cheapest to expensive

1. this could be cause by 87 octane gas since on higher octane ratings i didnt really have the same low idle.

2. need new air filter

3. need new spark plugs

4. need a tune up

5. off chance you could be getting a slight vapor lock in the fuel lines

these are just suggestions, YMMV

 

[99Black4R]

thanks nodak,

i'll give some of them a try this weekend. i recently purchased the 4R and not sure which maint. has been accomplished. spark plugs and air filter will be the first. perhaps a throttle body cleaning is in order. thanks for the assistance.

 

[NoDak]

depending on the mileage, if your over 60k, the spark plugs may need replacing. toyota rates the platinum plugs between 60-100k. i usually replace the spark plugs at 60k.

also if you can find a really dark location, lift the hood and see if you can see the spark plug wires arc ing (blue color). thats a sign you may need to replace the wires also due to cracking or leakage in the wires. had this happen on my 84 celica.

 

[jharris2]

also if you can find a really dark location, lift the hood and see if you can see the spark plug wires arc ing (blue color). thats a sign you may need to replace the wires also due to cracking or leakage in the wires. had this happen on my 84 celica.

I agree that the plugs is a good place to start. Also, since the plug wires are from 99, I'd probably go ahead and replace them anyway, if you can afford it. That's one area that can go bad without you realizing it, and replacing them is usually not very difficult -- you're already half done when you pull the plugs.