Throttle Position Sensor??

On a cold start it idles at almost 1500 rpm. After shifting into drive (or reverse) the rpms drop instantly too 700 or so . After doing errands etc and starting back up it still idles high but not as high as a cold start Tonight it also seems to be idling a lot more rough , almost making a knocking sound while stopped with foot on brake. My check engine came on the other day and read the p0120 code, cleared it and hasn't came on since. I ordered a new throttle position sensor already and will probably clean throttle body as well. Any other thoughts or ideas ?? Thanks in advance guys

 

Yeah on my tacoma after cleaning the throttle body and iac it would high idle for a week or 3 than one day idle normally

There did t seem to be a rhyme or reason to why it stoped

 

Recommend complete removal and cleaning of the throttle body and IAC. Also check the IAC gasket while you're cleaning it.

 

I had the same issue once but had to go further then cleaning the TB and IAC valve to solve my idling issues. But according to a few posts here when I had my issues, after cleaning the TB and IAC valve you're supposed to reset the ECU by just disconnecting the battery and reconnecting it then after driving for a few days, the ECU will find the right fuel/air ratio and it should run back to normal in most cases but not for me lol

 

OP as far as your idling issues, I had an issue on my 3rz where on cold starts, the engine idled rough and after it warmed up it would run normal. I started by cleaning the throttle body and iac valve (definitely needed a cleaning) then the cold start rough idling went away but it another issue came up and it started to have the same problem as yours idling high in neutral or park and when put into drive it idles lower but not as low as it should be. So I replaced the IAC Valve with a new OEM one and it idled better but still not idling within factory specs. Oddly enough I spoke to a LC Engineering tech and he told me to check my Engine Coolant Temperature Sensor so I replaced it and idling issues went away! I have a 4 cyl 3rz but I thought I'd just give you my input when I had the issue.

 

Remember it can be the complete circuit not just the sensor

The throttle position Sensor is easy enough to check before replacing.

 

So I replaced the TPS a couple weeks ago or so. Everything seemed fine and it wasnt idling as erratic. However just a few days ago it started acting up again. Sitting in park it drops below 500 rpms and feels like its going to die . From a stopping position like at a stop light when you push gas it kind of cuts out . Feels similar to spark plugs being out. Idk what's going on but it is way worse off then it was before I did the TPS . Not sure if this is related or something different but any thought you guys might have I would really appreciate ! Thank you

 

By chance is your AC on and it is not idling up like it should.

Are you getting any new codes ??

Air Filter and fuel filter when were they changed last??

 

Ac is not on . And fuel filter I changed last fall but had trouble getting the bolts on either side tight. Not leaking though obviously. And air filter has not been long either but I will check it and see what it looks like . I also had all ignition coils and spark plugs wires replaced recently , could it be possible one of those is loose ? Or a wire arcing ? Idk I've looked everywhere and camt figure this out . I also sprayed some cleaner on throttle body and checked MAF sensor this fall amd that looked ok . But maybe should check again ...

 

Also my check engine light has not come on at all during this . It would come on periodically before I changed TPS but havent seen that since replacing that

 

Did you set the TPS position correctly when you bolted it on? Usually you need to use an ohmmeter to set it so it detects when the throttle is at idle. I'm not sure the exact procedure for 2000.

 

I believe so cuz it has those little grooves that fit together and it's the only way to get it flush . But I will check that just to make sure . Thank you

 

Maybe on the 2000 there is no adjustment like older models. You'd have to check the repair manual.

 

Think I fixed a similar issue with a change of spark plugs dog

 

Im having a rough idle only in D or R at a redlight after warmup, done everything under the sun, just bought an oem ect sensor today gonna try install soon this week, any tips on how to install like a video, cant find anything

 

You working on a 3rz?

 

Yes, already installed ect sensor and no luck, same rough idle.

 

Heres the resistance values for the tps in case anyone happens to be on this thread years later! From my understanding adjust the screws until the values you get match the ones in the picture!

 

you still going thru this issue? Did you solve it?

 

A bluetooth OBD dongle with the free Torque phone app features a widget to see the throttle position in real time, either that or techstream can be used to see the values.

It looks like the 5VZFE TPS is not adjustable, but maybe some years and options packages had the one with elongated mounting holes.