At operating temp, idle speed is ~700 rpm. But in gear I've noticed that it's at ~500 rpm or less. I understand the engine is under load while in gear but the low engine speed causes a slight vibration when in gear at, say, a stop light. I fully exchanged ATF with M1 synthetic and noticed no difference. Is ~500 rpm normal engine speed when stopped in gear?
Idle speed in gear too low?
- Thread starter rondoggnuts
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- Thread starter
- #3
So I assume you don't think it's not normal either. It's really not too bad, and a passenger would probably never notice, but it just seems a little low to me. I recently acquired my LX with 45k miles, and I honestly wouldn't be incredibly surprised if this was normal, though I would be a bit disappointed.
To answer your questions, this is with A/C either ON or OFF, and no CEL or anything else abnormal. Just very slight vibration and low RPM. If I shift to "N", of course idle returns to normal at 700 RPM. This is what lead me to believe new ATF would help solve, but no difference.
I'm still in the process of getting her up to par in terms of maintenance. So I've also drained diff/transfer case, changed air filter, cleaned MAF sensor, and some other unrelated stuff. But I haven't cleaned the throttle body yet. I'm also currently running some Techron concentrate in the tank, but the low idle is still present after burning a few gallons. I also have a bunch of BG 44k so maybe I'll run a can of that through.
Can you tell me where the RPMs are typically at when stopped in gear? Perhaps 600 RPM??
I have the 4 speed tranny, by the way, in case that matters.
To answer your questions, this is with A/C either ON or OFF, and no CEL or anything else abnormal. Just very slight vibration and low RPM. If I shift to "N", of course idle returns to normal at 700 RPM. This is what lead me to believe new ATF would help solve, but no difference.
I'm still in the process of getting her up to par in terms of maintenance. So I've also drained diff/transfer case, changed air filter, cleaned MAF sensor, and some other unrelated stuff. But I haven't cleaned the throttle body yet. I'm also currently running some Techron concentrate in the tank, but the low idle is still present after burning a few gallons. I also have a bunch of BG 44k so maybe I'll run a can of that through.
Can you tell me where the RPMs are typically at when stopped in gear? Perhaps 600 RPM??
I have the 4 speed tranny, by the way, in case that matters.
My '01 LX idles at about 750rpm in neutral, when in gear it drops a bit, but not more than 50-100rpm. According to the FSM, neutral idle speed should be 700rpm +/- 50rpm. 500 seems a little low when in gear.
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- Thread starter
- #5
Yeah, that's what I thought. I'll have to look at the FSM files that I have (missing some) and poke around some more. I think cleaning the TB is a good idea but I honestly can't see how it can cause this since it's fine in neutral. Seems to me that this would be tranny or torque converter related, but I could be wrong. I also just changed the tranny fluid so maybe it needs some more time to work it's "magic" perhaps? I don't know, anyone else have an idea what can cause this?
Last summer I got same symptoms with my 99LX. It was not that bad, but in about 2 month I ended up with CEL dropping code P0505.
Felt some positive difference after cleaned up TB.
Along with board CPU and multiple sensors, TB is a part of complicated fuel mixture system feedback, that especially sensitive at idle RPM's. The dirt, collected in it may get sticky and resistive to choke movement. That makes wrong engine response to torque variations.
Felt some positive difference after cleaned up TB.
Along with board CPU and multiple sensors, TB is a part of complicated fuel mixture system feedback, that especially sensitive at idle RPM's. The dirt, collected in it may get sticky and resistive to choke movement. That makes wrong engine response to torque variations.
- Thread starter
- #7
Interesting, I appreciate that info. I'll definitely take your advice and clean it up. I'll tell you how it looked before cleaning and if it makes a difference afterward.
That does seem worrying. I posted about a low idle issue when I bought my truck... it was caused by me resetting the battery and having the truck "learn" idle wrong (I was giving it gas). I even started to stall out.
When in gear, my truck kinda resonates.. shakes the whole truck. It's a bit annoying yeah. But it's definitely not as low as 500.
I'm resurrecting this oldie
I just bought a 2001 LX470 last week and I'm noticing the exact same condition as the OP. Was it the TB? Anybody ever figure this one out?
I just bought a 2001 LX470 last week and I'm noticing the exact same condition as the OP. Was it the TB? Anybody ever figure this one out?
