I own a 2009 LC with a supercharger installed by Sparks. It ran great for the first year and then started having issues. I have been working with Tony at Uni Chip and am now on my fifth tune. The previous tunes appeared to be too rich and I ended up replacing the air/fuel sensors four weeks ago. The MAF was replaced a year ago. Now the truck runs great except at idle. It is idling around 500 rpm and at times dropping to 400 rpm. Once it stalled at a light. The drop in rpm is more pronounced when coming to a stop. Uni Chip, Tony, says their product doesn't control the engine at idle. My friends at the local Toyota dealership are stumped. The truck isn't throwing any codes. The truck has just over 100k miles. Any ideas?
Help diagnosing low idle
- Thread starter lgop
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Atwalz
Civil Engineer
Rpm seems to be low. Standard should be 650 to 750 with tranny in neutral and Ac off. Have dealer check the timing it should be 8 degrees. Then again these specs are for naturally aspirated engine. Not sure how these would differ with supercharger. I would check air filter, spark plugs, and clean throttle body. Also, have dealer hookup techstream laptop on test drive and monitor the parameters that are out of spec. Good luck.
- Thread starter
- #3
After my first post the Toyota dealership diagnosed a misfire on #4 and switched the coil to #1 and the misfire went away. The next day there was a ECU failure code but it cleared itself. The idle has been erratic and after researching the issue on the Tundra forums I decided it was time to take a look at the throttle body. The pictures show the issue. I soaked/scrubbed/cleaned everything and unplugged the negative terminal for ten minutes, and now the LC runs great. I also used a can of computer cleaner to blow out the MAF. I am guessing the sludge is from the oil on the TRD performance filter and fine bust that happens to pass through the air cleaner. I have switched to a dry element air cleaner. I hope this helps someone in the future.
For what it is worth---I installed a TRD SC on a Tacoma and then ran a K&N air filter. The oil from the filter fouled the MAF. Had a similar problem on the FZJ80 running an oiled filter. I stick with OEM dry paper filters now. I don't think that either filter was "over oiled" but that is a judgment call. So your findings don't surprise me.
Thank you for following up with the solution.
