i have a 4runner with a 3.0 and was wondering why it would be running rough at idle. I did the diagnostic test and it came up with codes 13 and 71. what sensor would make it run rough at idle?

 

Code 13- RPM Signal-- NE signal is not input to ECM for 0.1 sec. or more when engine speed is 1000rpm or more. Trouble areas: Open or short in NE circuit, distributor, ECM.

Code 71- EGR System Malfunction-- With the engine coolant temp at 60C (140F) or more, 240 seconds from start of EGR operation. The EGR gas temperature has risen less than 20C (36F) during the 240 seconds.
Trouble areas: Open in EGR gas temp sensor, Open in VSV circuit for EGR, EGR vacuum hose disconnected, valve stuck, clogged EGR passage, ECM.

 

so the rpm signal would probly not be the idle problem, what would be then? the egr valve is bad, would that make it idle rough?

 

The egr thing could be the problem. according to toyota4x4907 The EGR gas temperature has risen less than 20C (36F) during the 240 seconds. I would start by looking for a exhaust leak. if the exhaust is leaking it isn't flowing through the EGR valve. Also you would be loosing some back pressure so it could cause it to run rough.

 

i have no exaust leaks at all, could the egr valve just be shot?

 

Try replacing the EGR valve with one you know works correctly.

Its possible the rough idle isn't due to either of those. How rough is it? Do you have an auto or manual?

 

I agree it could be a number of things causing your rough idle. Is this a new thing or is it a ongoing problem. Have you done any work to the engine? or did you go out wheelling and it started running like this? what year is it? I can look it up in mitchell ondemand.