91muddog

remove the fuel filter and blow in it, it should be fairly easy.

if the fuel filter checks out let the truck sit for a day or so and have someone start the truck while you watch the tailpipe. look for a bluish smoke.

toyotas have been forever infamous for oil seeping past the valve seals which if a fairly large quantity could cause this.
how many miles are on the enigne itself?

thegreydog

I am currently getting a 5 and 6

That was another option I thought about, but this is really weird, no matter how high I turned up the idle, it just plopped faster, kind of like a stroker motor.

A little condensation sometimes, but no smoke. The valve seals are new and were check when we re-tightened the valves.

It may crank and run right today, who knows? I am starting to think about vacuums. What vacuum device or hose is related to idle?

thegreydog

On the way to work, it straightened out again, back to running smooth. I am going to stop by the parts house and get another cap and see if that fixes it.

91TPU

i noticed that when you get aftermarket caps they dont come with the little gasket that was previously on there, and instead of finding a new one, just use some black rtv to prevent moisture buildup in the cap itself...thats what i did, and my rough idle when cold went away...i doubt this is going to solve your problems, but alteast no water will get in your cap...

MudHippy

So you've replaced the O2 and are still getting that code, have you cleared the ECU memory? Technically, if you've cleared the codes and it keeps popping up, "then the repair was unsuccessful" that's what it says in my book. I don't quite get how you might fix the 6, could be the distibutor I imagine. Have you tested the ignitor coil?

JEBSR5

I think Mudhippy was on to something there about bump stop adjustment. There are actualy two things there that can be adjusted, I believe. One is the dashpot that keeps it from closing too fast to prevent backfires and another is to keep it from shutting too far period.

I would have to look at mine, but pretty sure there are two adjustments there and not just the dashpot one.

MudHippy

Yeah, that deal. It's a little hidden on my 3.0, closer to the throttle body than the dashpot. It's tricky to adjust, but once I got the hang of it, it makes mine quit actin' like he's talkin'. Not too tricky really, there's a noticable change at a certain point in the adjustment, STOP there and make sure it won't fall below that point. It's strange, like when it's not set right the idle will want to be lower than it should be for whatever temp the engine is at, and rougher. If you get that set right though it makes the idle smoother and respond better to the idle adjustment screw also. I couldn't get my idle smooth enough to correctly set my timing till I got the whole thing figured with that limiter adjustment screw (allen head on mine, with a 5/16 nut that loosens so you can adjust it) for the throttle plate dealy, whatever it's called.

Joey

Funny how there was water involved both times that you mention this happening. Coincidence?

thegreydog

Yesterday I spoke to a Master tech and Ted at engnbldr. Both suggested that the TPS is probably causing it to run rich and dump more fuel causing the O2 to trigger. I have found the tutorial on how to adjust the TPS, but can someone tell me how in laymans terms, I am not an auto mechanic.

NaeSLaS

link to the tutorial, and i'll translate for you.

thegreydog

http://www.4crawler.com/4x4/CheapTricks/TPS/index.shtml

thegreydog

By the way I see the screw on top, but how do you get to the screw on the bottom?

NaeSLaS

ok, so basically you need feeler gauges, and a multimeter.

first, see how it works. Set the multimeter to resistance (ohms, or the omega symbol), and notice the reading. Now touch the terminals together. 0, right? so basically it is measuring how much voltage can get through whatever you put the two plugs on.

touch them together, 0 resistance, lots of voltage (as is common for most wire).

next, go to your TPS. put it on the 2nd and 4th pin (according to the diagram). Now, move the throttle butterfly open and closed. notice the number changing? Thats how the computer knows how open your throttle is.

now, we have to calibrate it. We want the value of the throttle being opened a certain amount, to tell the computer the correct value.

You basically put the right feeler gauge in there to open the throttle to a premeasured amount, and then adjust the TPS so that the reading is correct, as specified to the table. Do this for all the positions (including WOT), and voila. Calibrated.

Does that make sense?

Edit: You probably have to take the TPS off, and set it on the workbench.

JEBSR5

It's definately easier to do off ten on, but not impossible to do it on. Since you need to check the throttle plate stop and daspot, it would be easier off. If you need to replace TPS, then it's easier off too. That way you can be sure TPS is aligned with TB tangs. You can also flush out the coolant passage, IAC and clean TB easily off.

TC22RE

Just a thought, not sure if anybody mentioned it before but... did you check the throttle bore to see if it was dirty? If you remove the plastic pipe that runs into your intake from your air cleaner and just look into your intake at your throttle plate does it look dirty? Black gunk around the edge, open your throttle, does it look dirty on the back of your throttle plate? You may want to clean that out, it will cause the problem you're having. I've seen motors idle like complete dog ˟˟˟˟˟ with dirty throttle bores but run great at open throttle... Maybe you're bore is so dirty that its clogging up your idle air adjustment screw and thats why you're not getting a change in idle when you adjust it... Seen that before as well.