Intermitant ignition?

[csrobb007]

Strange thing this morning...35mph, snowing but road was like driving in a lake in spots, rpm at about 1800ish, truck seemed like the ignition got wet and started stumbling...let off the gas...truck idled just fine, no miss, nothing. Press on gas pedal, rpm rise to 2000, then it was like a rev-limiter kicked in...let off gas, idled just fine. Pulled over to see if something got wet, sucked water, whatever...nothing. Revved the engine...2000 and cut out...idled for about a minute or so while scratching head...jacked the throttle again...no problem, rpm'd like a champ...no problem since.
I would chalk it up to water, but it was always at 2000 rpm, and didn't sound like water in the cap/rotor...air filter can was dry, and nothing seemed out of place. Are there rev-limiters on the 3.0 for any reason? Fluke glitch someplace? Some sensor that is going away? Ideas? Am I f'n stupid, and missed something obvious?
I've just got this thing tuned and running like a watch (as much as a 3.0 will allow), and it just seemed strange when it happened.

 

[DC runner]

Doesn't sound like water at all. Water doesn't care what RPM your at, and a hydro locked engine makes itself apparent REAL quick.


Honestly, there are a TON of things that could be causing this. That engine of yours has a ton of vacumn lines that run all kinds of things, and 1 little crack in the line can cause all kinds of issues.

It could be a fuel pump/filter issue. It could be the distributor. It could be your coils.

No rev limiters on the 3.0 but tons of little things that could be causing this.

 

[77'911]

I guess the first thing that might be on my list, if it has not been replaced, would be to install a new EFI relay. They can cause a whole host of electrical gremlins, and the relay is about $12 at the dealer. Our local dealer keeps absolutely nothing on their shelves unless they are rolling through the part. They had a stock of them.
What your describing sounding like what our 4runner was doing until it went to a crank/no start and just no crank.
regards

 

[csrobb007]

No hydra-lock...done that and shoved two rods out of the block...just a stumble that didn't allow the rpm to climb. Correct, water in cap is not rpm specific, so I ruled that out. Thought mabey it was like the early Chev throttle position sensors when they got wet, and didn't give correct readings due to moisture...blah,blah,blah. It was just strange, it always runs good, and then just a hickup.
I just thought it was a stuck solenoid of some kind, with so much vacuum opperated **** on these things, and in need of another serving of "rice wine"...(Seafoam): through the system.

 

[csrobb007]

OK, the damn thing did it again...bouncing between 1500 and 2000 rpm. When the "cutout" happens, it sounds like a valve of some sort opens on the passenger side of the engine, below or around the intake and near the valve cover.....PCV? I don't know what the other valve is with the thermocouple connected to it is, but sounds similar to when the engine is first started and some kind of bypass is happening with exhaust...?
Given my lack of understanding of these components, can they or do they stick (open or closed)? and what the hell do they do?
WTF?

 

[csrobb007]

I looked through the FSM available here, and found a possible part/issue that may be the culprit...? The (PAIR) Pulsed Secondary Air System...mabey...
Would this system limit RPM climb if malfunctioning? Seems to have a connect to the ECM, the air flow meter at the air cleaner, and or the TPS.
Would not letting the engine reach complete warmup before driving during cold weather cause a situation like this? The manual says it will turn the valves/system on during deceleration OR RPM between 1200 and 3200 with coolant temp above 95 degrees..OR coolant below 77 degrees.
Given it's getting colder (last night was 19), mabey take a few extra minutes to warm the truck up?
It's only done it twice, conditions were not the same, two days apart, no common denominator in the scenario. I leave on another one of my twice a month trips to Washington, and would hate for this problem to park my family on the side of the road in the middle of nowhere in the snow.
Again....anyone ever had a problem similar?

 

[77'911]

You might have a combo of problems going on, but you might address the "warming up scenario" 1st. It sounds like the fan clutch might be on the way out or the t-stat sticking. With our bmw, it is the fan clutch which I am about to replace in a month. The car will warm up if it is in stop and go traffic for a bit, but driving in this cold weather currently it stays well below the mark it should for the factory t-stat.
If your having secondary emission, or crankcase ventilation issues, check the following:
-pcv(pass side valve cover, see pic)
-egr valve
-check vacuum hoses off intake
regards

pic: when I resealed the fuel injectors and intake, replaced valve cover gaskets/+pcv

 

[csrobb007]

It's done it again.. See "Emergency" thread. This time I'm stuck 400 miles from home with wife and daughter. Still have the "rev-limiter" type effect that is not allowing the rpm's to climb above 1800.