tropics

Aurightyy,
Need the help from the gurus for my problem. I have searched and read many threads and nothing I found exactly resembles what my 4runners doing, lots of good ideas, just trying to see if I can narrow this down some. The background, 94 4R, 3.0 VZE, about 180K miles, plugs about a year old, was running about as perfect as a 16year old motor will. Head gasket was redone about 80K ago, timing belt say 20K ago. The problem, just recently on a cold start I would need to crank it longer than usual. The first turn of the key crank then stumble, rough idle, then die. The second crank, it will usualy crank and run okay. Been doing that for about a week, now new twist, after the I get it running at freeway speed starts to stumble and lose power. After feathering the throttle it went away. That has happened once, I havnt driven it yet since it happened. Oh, also, no CEL either. Any ideas? Ignitor? VAFM? I know the intermittent part makes this a hard solve. Open to your ideas!

Mahalo

aa1911

iTrader: (1)

mine had similar idle issues, no high end problems though.... I did a good cleaning of the TB/Intake plenum, replaced plugs/wires, PCV valve, EGR and tested all my engine control sensors with the DMM. The one thing that was causing my problem was a clogged bypass space in the TB, the small port that goes around the throttle plate. my intake plenum was full of carbon from the good ole EGR, went thru 2 cans of TB cleaner...

I'm no guru but would recommend the usual checks; all the sensors (bust out the chilton or haynes for the resistance specs on the sensors), fluids flush/replace, plugs/wires checked out, hopefully it's nothing major.

that's just my 2 cents for what it's worth

aa1911

iTrader: (1)

this probably has nothing to do with your issue but I always throw this out there; the front (pre-cat) O2 sensor should be replaced every 75k - ish, they go bad before the CEL will come on and rob fuel economy. I went from 16mpg to 20mpg from a new O2 sensor alone... not kidding.... $70 from URD

tropics

Thanks,
going to try and check the ecu to see if a hidden code was thrown. Will also check the bypass tube in the TB. Was also thinking possible cold start injector? not that it gets below a chilly 70deg in Hawaii. It allmost seems like the engine gets a little flooded when cranked for the first time.

tropics

Following up, got home last night and was able to pull the code 14, weird that the CEL wasnt illuminated but the code was there. But it does make sense for the harder starting. So after reading about code 14 on the forum I checked the ignition coil, the inner resistance measurement was .6 the manual states the range should be between .35 and .55 . The outer measurement was within spec. Now do you think being .05 out of range is a probably cause for the problem? maybe why its only a intermittent problem? Not against spending the money to change the ignition coil but would hate to throw money at this and find it doesnt solve the problem.

aa1911

iTrader: (1)

I think the resistance specs are very accurate, had a bad VAFM before and the resistance was just barely out of spec, vehicle wouldn't even run (no CEL either). after cleaning it and 'rebuilding' it, I got it well back within spec and it worked perfect. My guess is you found at least the majority of your issue, unless anyone else has better advice, I would replace it if it was me. Even if that wasn't the sole cause, it certainly will be shortly down the road I think

Glad you found something! good luck

tropics

Okay, quick update, I picked up a new ignition coil and tested the resistance, it was exactly the same as my old one, .6 but hey, no return on any electrical parts so I figure cant hurt and change it out. I figure gotta start eliminating variables someplace. Give it a crank and it doesnt turn over on the first crank. Oh well, it pretty much runs the same as before, some times it starts on the first crank, sometimes not. I'll see how it goes and figure out if I need to look further for other reasons why. Thanks aa1911 for your input!

Mahalo!

tropics

Okay, update to the story to help out anyone else with a similiar problem. After changing the ignition coil truck was still hard starting, yesterday morning it took 6 turns of the key to finally get it going. Clearly the ignition coil wasnt the problem. After trouble shooting it with the hood open and beer in hand staring at the motor, turns out it was the spark plug wire that connects the ignition coil to the distributor. I had changed it a while ago to the Jacobs wires, must have not been seating good since it was loose and terminal was corroded. Cleaned it up and it started on the first crank this morn. Moral to the story, sometimes them stock Toyota parts work better than them fancy replacment parts, my bad. Will probably change the wire set back to stock. Thanks to all.

aa1911

iTrader: (1)

glad you found the problem, thanks for posting that up for us. must be a good feeling!

When I changed my wires last year, I tested the resistance on both the old and new sets and the old sets were actually pretty close (still well within spec) to the new ones. had to change 'em though cause when I changed plugs, even being super careful, one of the wires ripped apart in my hand. the new ones I bought from autozone were harder to seat than the OE ones I remember.