Rpm problem

So I have a 2001 v6 manual 4x4 tacoma and its been having some issues with the rpms/idle...first when I started it up it would barely idle and I could have to keep my foot on the gas till it warmed up, so I replaced the idle air control and it fixed that. Now while driving the rpms rev out super easily and in 5th gear going about 55 the rpms are at 3000-3500 rpms and idles at 1100 does anyone know what it could be?

 

If your RPMs are changing while in gear without a change in speed your clutch is slipping and is toast.

You can verify this by driving into/up to a tree (very slow) and put on parking brake (this is so truck will not be abel to move forward), put it in 5th gear and slowly let out the clutch. If the clutch is good the truck will immediately stall, if its slipping it won't.

The high idle seems unrelated.

Driving while the clutch is slipping will leave you stranded very soon.

 

Tried your theory and it stalled right away...the idle doesn't move up and down when I have it in neutral it just idles at a steady 1100. It's when I'm driving it seems like the rpm gauge moves up to quick when I'm going from 1-5th gear

 

I think it may be a clutch aswell. I've had my clutch go out on me last year. The clutch was pretty soft for a truck, and when it got really bad, the transmission(clutch) would slip on the freeway. I would give it throttle and engine would rev with it in 5th gear but no acceleration. I wasnt able to maintain the speed limit any longer. Put a new clutch in and it solved my problems. Was a pain in the ass to do too.

 

Is the transmission in low range? This should only be possible if you are in 4 wheel drive, and I'd think you'd notice it binding in the corners if you were. This would explain the high rpms.

 

No it's not in 4wheel! May be a vacuum leak?

 

There is a direct physical connection between your engine, transmission and wheels. It is impossible for the RPM to be different at a given speed (55 mph) than it was in the past unless something is broken along that connection. This is why a few of us suspected the clutch. This is the most common point that wears out along that path. You originally said the RPM was 3000-3500 @ 55 mph, again, the rpm cannot vary at a fixed speed in a given gear. The RPM at 55 should be exactly some RPM (I don't know what ~2500? maybe) and will never be different for that gear and speed. (FYI if you had an automatic transmission then things are different.)

If you tested the clutch and it seems fine, perhaps the explanation is that your RPMs are not changing, but that the tachometer (which displays the RPM) isn't working correctly. In other words, your RPM is the same as it has always been, at idle and at 55 mph, but it looks like it is different because the tachometer is malfunctioning.

Doe the engine sound like it is idling at 1100 rpm instead of ~750, does it sound like its @3500 instead of whatever it typical was at 55mph?

 

If it is not the clutch it could be the RPM gauge itself or whatever is sending the signal since the idle shows high as well. If the engine idle sounds normal and RPM shows 1100 or so I would check whatever sends the signal to the RPM gauge as well as the gauge itself with a OBD computer. Something like a UltraGauge or ScanGauge to see if what it shows matches the cluster.

--Dan

 

The idle does seem a bit high!

 

Interesting. Though I would think it unlikely, basically its going to be a cam or crank position sensor that is sending the pulse signal to the ECM, which is then sending voltage to the cluster (im saying this from common experience, im not familiar if this is exactly how Toyota does the Tach signal). Thing is, if you hook up a scanner, it is only going to reflect the reading the ECM is sending out, youre basically assuming that there is some kind of short or other circuitry issue with the cluster. Possible, though unlikely.

Just to state the obvious. I would also rule out vacuum leaks, possible lean condition could be the cause of a faster idle, as well as compression loss. Good old vacuum gauge at different manifold points.

How many miles on the clutch? Has anyone asked, does it FEEL like its slipping?

 

I agree, it sounds like your tach is bad or the sending unit for it has a loose connection or it is bad.

one thing not yet asked here is do you actually "hear" the engine revving up that high or is it just the tach saying its that high?