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Couldnt find answer - revs get stuck above 3k, EDIT Answer Found
EDIT: It was a piece of rubber stuck in the butterfly valve. Scroll down to see a picture.
The car is a 95 LS400.
I'm not sure the two are related but this problem put a bad taste in my mouth. I bought a beat up LS so I was expecting problems. I fixed what I thought was all of them and then...
One day I realized the car is in PWR mode and not NORM. In the interest of saving gas, I put it into NORM. Now, I should mention, the light that shows ECT didn't show up - only if its in PWR. But that's not the problem. Maybe related - it's the only thing I did before this happened
I went to take my wife to work and on the way, once the engine hit somewhere 500-1000 before redline, it gets stuck revving at that range. It transmits power to the wheels so I don't think it's the transmission, correct me if I'm wrong. I had to put it in neutral and shut it off.
Now, some "diagnosis" if you can call it that. Opening the hood and playing with the throttle resets it and the car is fine again until a certain rev range.
I can put it in neutral, rev to 2k, it comes back down, 3k, still comes back down. Around 4k however, the revs don't come back down. This tells me maybe something is getting stuck?
I haven't looked at the butterfly valve but the whole system LOOKS to work fine with the naked eye. Everything moves as it should and comes back to original position EXCEPT I noticed that the cable, the one attached to the part you push down to open the throttle while under the hood, goes slack when it seems like it should be sliding back into the encasing. Am I wrong? I can press it down to give the cable slack and indeed, the cable moves in and out of the encasing when I use my hand. Is this it?
The only other thing I can think of is that I was messing with the intake. Long story short, I was trying to remove the accordion-like part that attaches to the plastic part and, well, it cracked in a few places. So in the interest of not destroying it, I connected it back. However it makes me think - could a piece of rubber be in the butterfly valve or something?
I read everything I could on this and no answer. I found another similar post with no answer.
Last edited by Rokas; 06-09-17 at 06:10 AM.
Reason: Found answer
Maybe the throttle position sensor? I'd start by checking it. Can unplug with engine off and check the resistance in the various throttle positions.
Can you tell me what readings I should be seeing? My pops didn't know and I don't either. Last night we were looking at it and it seems to me it's the sensor or the butterfly valve must be stuck open. The car now seems stuck revving itself... doesn't reset when I play with the throttle anymore. I'm going back today to take off the intake and see. I really hope it's just something easy that's stuck and not an ECU or electronic problem...
Wow good catch. That is a strange one, I don't think anyone would have guessed that. What is strange is you said at over 4k it wouldn't fall back down, and how come it just didn't suck that thing outa there. And thanks for posting the picture and the problem.
No problem, dicer. As for why it didn't get sucked in deeper - probably pure luck or Godly intervention, hehe. What would the effects even be? Blocked airflow I'm sure, and an engine that won't stay running... you would have to take the throttle body off completely to get it out.
06-08-17, 05:20 AM
Couldnt find answer - revs get stuck above 3k, EDIT Answer Found
