Fails to start, No idle

Hello everybody!

I have a 99 4runner, 4wdr, Limitted.
I have a problem starting the car sometimes. It happens very randomly, at least that's what I think. So basically I get in the car, turn the key on, and hit the starter. The engine sounds like it's about to start and as soon as you let the key go, the engine dies. No shaking or anything like that, just plain dead. If I hit the starter, but this time keep the foot on the gaz pedal, basically opening the throtle, the engine starts and stays on as long as I don't take the foot of the gaz pedal. If I do, the car dies the same way. If I put the car in netrual, start the car and keep the foot in the gaz pedal, switch to drive or reverse, the car starts going, and at this point it doesn't die anymore. You can just drive and the car takes off without any problem. You turn it off and on again, the idle with stuble a little but it will not die. Just hit the gaz pedal and it will pick up. So the trick was to be able to get the car moving, and the engine it will not die after that.
There is not check engine light on. So I've talked to my Toyota mechanic, and he wants to look at it but of course this is happening randomly, or I have not been able to pick up a pattern yet, since my wife drives it.

So I've been thinking about it. I've changed the fuel filter around 4 months ago, had fuel treatment about 2 miles ago, changed the air filter at the same time. I'm suspecting that the car is having problem maintaing idle/vacum. I'm not sure.

Does anybody have any idea based on what I've described here. Sorry about the length.

Cheers,
-Ledio

See if your compter has recorded any codes. Not all codes trip your CEL.

I don't know an easy way to do that, other then installing the software in a laptop and buying the connector that connects the laptop with the car computer. Do you??

Cheers,
Ledio

TrakAuto and others

I'm thinking of cleaning the MAF sensor this weekend. This is the one that's located right after the air filter. Couple quetions:

1. Do you think this sensor may have something to do with it?

2. Also is there any other sesor that I can easily clean?

I'm leaning toward anair problem rather then a gaz or electric problem since when I hit the gaz pedal which allows more air into the engine, the engine runs, but as soon as I take the foot off, the engine dies.

Cheers,
Ledio

You can also try cleaning the throttle body.
http://www.4x4wire.com/toyota/maintenance/30_V6/throttle_body/

Yes that too, but when I changed the spark plug wires, the throtle whas right there, very visible and I didn't see any dirt. I'm curious to know what controls the the air, or how's the air getting to the engine when you hit the ignition. What sensor controls that, and remember this doen't happen every time you start the car, but at least once a week or so. Also the idle is pretty week after you've driven in the hightway at high speeds. The RPM sits at 1000 or less sometimes.

Cheers,
Ledio

"The RPM sits at 1000 or less sometimes." Nothing strange about that. If I remember correctly, the idle speed is 700 rpm.

What controls the air? The ECM controls the throttle position by monitoring the rpm, through pulses from the crankshaft position sensor (if I'm not mistaken). The throttle position controls the air quantity.

If you're talking about what controls the mixture, then it is the HO2 sensor (or A/F ratio sensor) in the exhaust manifold.

Check the codes

Thank you Brian.

I'll clean MAF sensor this weekend, and also I'll look into downloading that software in my laptop for checking the errors. I need to get the connector too, which is a little expensive like $100, but what the heck, one time purchase. I don't know what else to do, the mechanic here will charge me $110 per hour if I take it there. :(
Also somebody mention to me to do a pressure test to the engine. I'll check around to see if anybody has done that before to a 99 4runner.
Hey by the way my Toyota mechanic told me last time I was that the spark plugs needed to be changed with Toyota factory one instead of after market one like the botch ones I got. Is this true? If so I need to replace them with Toyota ones, since it may be a problem

Cheers,
Ledio

Don't you have access to a TrakAuto or other parts store that will check the codes for you free?

Never heard of them. I did a search at yellow.com for them, but nothing.

I finally took the car to another mechanic. He told me that the problem is with the "Idle valve control". I needs to be replaced. Total cost $612. I don't know if that's sound right thought. He is charging for diagnostic too. That's a lot of money. I'm also wondering that the part itself maybe expenssive.

Anyways, I'll let you know what will happen. Hopefully this will fix it.

-Ledio

Good Luck