Threeveezee-EEE intermittent dead cylinder?

[TimberWolf]

Alright, so i've got an 89' 4Runner 3.0 with about 273,000 on the clock, been in the family since new and have had pretty much zero problems with it...

two days ago, amoungst the sub-zero Colorado temperatures and snowstorms it suddenly felt like it lost power. the engine shakes the bejesus out of the truck whenever you give it gas, and at idle the exhaust has gone from a pur to more like a motorcycle...

no ECU codes or light, sounds like a dead or consistently misfiring cylinder.. threw in a new set of OEM plugs just to rule that out with no change (when i did a full tuneup in 2006 i used everything OEM except for the plugs , figured i would do them anyway)

sprayed carb cleaner all over everything... couldnt find any vaccum leaks.. did a half dozen or so other checks, then got lazy in the cold and decided to run it to my shop to diagnose it for me...

so i go and fire it up after screwing with it all day to run it to the shop, and its magically running perfectly fine!...yay! crisis averted!

So i drove it around all day yesterday with no problems, and all day today, then as i finish up my last stop (had to get my pankcake fix) the problem is suddenly back!

So what gives? still no check engine codes either.. i was going to do a compression test but the problem went away before i did, and even so, bad compression would be a constant problem wouldnt it? not a 100% on or off type thing? perhaps a fuel injector that is in its death throes?

No smoke or any signs of a blown head gasket, been poking around the wiring to see if theres any loose connectors.. what would cause it to go away and come back again a day later? thanks in advance!

 

[bouncin betty]

My father had a similar issues with the 3.0 in his T100. He took it to service departments etc. Struggled with it for almost a yr. He was advised to try "seafoam"b from a friend. He had nothing to lose so he dumped some in with his fuel. It fixed the bad injector and has not had the problem since. 2 yrs now.

I use Sea foam in all my pieces of junk that I am trying to keep running. YOu can find it at auto parts stores. Good luck. I hope it works.

 

[TimberWolf]

hmmm, sounds like it would be worth a shot, i have multiple peices of junk that im trying to keep running, so perhaps i should bust some out!

I used a stethascope on the injectors on the right and they "sound" as if they are working without a hitch, however checking those ones under the intake is going to take some contortionist magic and for a tad warmer weather! i've heard if you find one thats not working, that if you "bonk" it it might free something up and cause it to start up again... if thats the case i've got some bonking to do!

 

[2ndGenToyotaFan]

Maybe a sticking valve... Check the rubber intake boots for tears... I hate intermittent problems... Sounds like you're on the right track, but it's difficult to diagnose when it won't do it all the time... Good luck!

 

[Bogo]

What about the wiring controlling the injectors? A broken wire could make for an intermittent fault.

 

[toyminator]

What about the wiring controlling the injectors? A broken wire could make for an intermittent fault.

I had this same problem on a 22re. A broken fuel injector wire inside the harness was causing intermittent failure of the fuel injector to spray fuel.

 

[Combat Chuck]

sounds like valves to me, had a similar issue with my mom's V6 F-150, sticking valves leading to the shakes and gutlessness. Anything else cylinder-wise would either be a tossed rod, which would pretty well destroy the block, or dead rings, which means blow-by, and not the shakes.
Injectors could be a problem too, or timing.

 

[TimberWolf]

done a bit more work on it now.. pulled the distributor cap and that little spring loaded button thing in the middle that contacts the rotor was GONE, and the plastic around it was all charred and melted, along with the contact point on the rotor.

I'm thinking that its a wonderful thing to be such an easy fix, so i throw a new cap and rotor on and...... it doesnt even have an effect! still running funny... hmmm.. time to dig deeper..

 

[raevenzero]

Pull plug wires one at a time and put them back. The one that doesn't make a noticeable change in the way the motor is running points to the bad cylinder.

I honestly think that this sounds like an injector. You may have a bad wire (which I have had on a 22re also...actually, it was the contact in the connector), a stuck actuator, or gunk in the screen.

I used to have to wiggle my connector around and tap the injector with a screwdriver handle. I ran on 3 cylinders for a long time before I figured this out and all of a sudden felt like I was driving a race car.

I recently pulled my injectors and found gunk in the screens. I don't know if it made it past the filter or if it formed somehow inbetween the injectors and the filter.

 

[TimberWolf]

Problem solved!... i think... Cylinder # 2 didnt change anything when i unhooked the plug wire. did a compression check and all cylinders are still around 160... busted out the stethacope again, and injector # 2 is ticking still but is VERY faint compared to the others. i think i nailed it, thanks for the help guys!