I recently had the CEL come on and the code that I read was P0171. I took it to the toyota dealer and they recomended a manifold intake gasket. The new gasket is the newest, reddish-brown, version. I replaced it, and now the car wants to idle around 550 rpm while in gear. Its only at about 800 rpm in park. I checked all of the hoses that I disconnected and they seem to be in place. If anybody has any pointers of where I should look for the problem please let me know.
I checked the vac hose in the back of the throttle body. It seemed to be in its correct place. I even took manifold intake back off to see if the gasket was pinched. When I tightened the bolts back, I did them from the center out. When the engine is warm, it just gets so low in rpms that it vibrates. Since I have owned the car, it would idle at around 900 in park and 800 in gear at a stop sign. I am just frustrated...
800 rpm in park is fine, and it does normally go down in drive... Give it some time to adjust itself.
What year is it and what's your mileage? Was your transmission fluid replaced yet? It is recommended at every 60000 miles.
Yes it had always went down about 100 rpms when in gear, to 800 rpms. It now goes to about 500 rpms when warmed up in gear. It feels like it is going to die, the lights get dim and it has some serious vibration. I have not changed the transmission fluid, but I do need to. This low idle problem was caused by something that my brother and I did while changing out the manifold intake gasket. It did not have an idle problem before we worked on it.
What year is it, and what's your mileage?
I assume the ECU was reset by disconnecting battery (or by removing ECU fuse for a while) when you replaced the gasket?
I think what's happened is that you've gotten used to a slightly high idle over the last couple of years and now that it's fixed it has a lower idle that you think is incorrect.
How long has it been since you did the gasket? Sometimes it can take a few weeks for the computer to fully relearn proper idle. You might be able to speed up that process by leaving the negative battery terminal disconnected for several hours to fully clear out the computer's memory.
It's also possible that you have a weak motor mount which is causing the vibration - you just didn't notice it because you had gotten used to the high idle due to the intake leak.
Toyota specifications fall for an idle of 650 to 750 RPM with the engine fully warmed up and all accessories off but I don't know if this is in park or in gear.
The idle had gotten higher over the last few months. But I have always paid attention to the rpms and they never got down to 500, even when the car was brand new. I do hope that the computer needs to reset and find its new proper idle.
Well I drove 50 miles to get to my Toyota dealer. I was at the stop light waiting to turn in and it started to act perfectly fine. I guess it did just need to reset itself. I was a 1/4 of a mile from spending unnecessary fees. In park it idles at 850 rpm and in drive at 750 rpm. What a relief! Thank you all for your help!
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