The 3VZE 3.0 engine had no spark and would not start. I had it towed and my mechanic changed spark plugs , wires, distributor cap and rotor. When the 4Runner came off the tow truck it started.

A few days later the 4Runner did not start again. I remembered that it started when it came off the tow.
I rocked the 4Runner back and forth, and it started .

so, where do I begin to find the no start problem?

 

power and ground. It's difficult at best to find a problem when all is working well, so when it fails... check for power on your ignition fuses. wiggle every ground you can find. wiggle harnesses and recheck to see if it starts.

 

Rocking a vehicle is an old school method of getting the starter to properly engage the flywheel (they are self indexing which means they are cut in such way they only need a tiny bit of "grab" at which point it pulls the gears together). You'll know this is a/the problem by the grinding, or spinning, sound of the starter. It indicates there is damage to the gear teeth on either the starter or flywheel.

You didn't give a detailed description of "doesn't start". You only indicated it had no spark, we're left to assume it turns over but didn't fire.

Inspect the distributor pickup (NE signal), it tells the ECU the engine RPM and is cruicial for firing the coil.

 

Yes, check ALL connections, and describe problem in exact terms.
Ex;
"crank" is when starter motor turns, as in cold-cranking amps rating of the battery.
"combustion" os when you hear "vroom, feel the engine vibrate and smell the exhaust, etc.
What exactly do you see, hear, feel when problem occurs?
AND I would not trust a mechanic who replaces things without verifying they are indeed broken and by replacing them he will solve the problem. If absolutely none of the spark plugs had spark, it is most likely NOT because of 4 bad spark plugs, nor all spark plug cables being bad.
Pls see my signature

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additional information:

I turn the key and the engine is turning over . I hear ( chug, chug , chug ) and feel ( vibration ) the engine turning over. no other sounds , that are hearable.

Thanks for your help

 

So what is your mechanic doing about it now? If nothing, and you want us to help you troubleshoot, get a multi-meter. (See my signature)

 

Automatic or stick? and when you say you rocked it back and forth was it in gear? Park? neutral? and ^^^ get a multi meter!

 

O.P.,
Like Akwheeler says^^^
Put model-year-engine-transmission-trim on your signature. Will help save everybody time having to ask and for you having to answer.
see my signature

 

 

rocking it like this will make the engine rock side to side, you may have a loose connection in one of the harnesses connecting the engine and body. Try wiggling one at a time or put your new multi-meter on DC volts and connect the black lead to ground and the red lead to your fuses and see if you have power to them (with the key on). any further testing will require a wiring diagram and some time.