07 tC, rough idle, bad gas mileage, slow acceleration
06-25-2012, 01:35 AM
#22
Junior Member
Join Date: Jun 2012
Posts: 4
Eventually I'll get to how I fixed rough idle at a stop, but the story is kind of important too...
I was having serious problems starting the engine with only 35k miles. It would take multiple consecutive cranks to initiate the engine. There was also a rough idle. I brought it to Firestone and they thought it ran fine but did a fuel injector cleaning anyway. It still had issues. I bought a new battery and installed it. Only then did I realize that the Progressive Snapshot device I had installed was setting off the fuel-cut off security system and messing up the fuel intake somehow. After I took it out, the car started fine, but the rough idle was still there...
A year later, I realized that when I changed the battery and had cleared out the ECU (I am not car-fluent), I did not properly RESET the ECU. I was suppose to LET THE ENGINE IDLE for 5-10 MINUTES! That's all I had to do! Everything runs normal now (except for the stupid noises coming from the hatch and minor AC rattle
)
So, when you change or disconnect the battery, be sure that the first time you start the engine you let your car sit and idle for 5-10 minutes. The computer has to learn the new idle. Sorry if this is obvious to everyone else on this board, but I had no clue. I mean the manual says not to let your car idle when you warm up the engine...Before you look at your throttle body, spark plugs, engine mounts, or whatever, be sure you've done this, especially when you don't have 100k miles or more.
Good luck. Hopefully it's as simple as my solution was. I'm going to repost this around since it was such an idiotic revelation.
Scion TC 2006 stock.
I was having serious problems starting the engine with only 35k miles. It would take multiple consecutive cranks to initiate the engine. There was also a rough idle. I brought it to Firestone and they thought it ran fine but did a fuel injector cleaning anyway. It still had issues. I bought a new battery and installed it. Only then did I realize that the Progressive Snapshot device I had installed was setting off the fuel-cut off security system and messing up the fuel intake somehow. After I took it out, the car started fine, but the rough idle was still there...
A year later, I realized that when I changed the battery and had cleared out the ECU (I am not car-fluent), I did not properly RESET the ECU. I was suppose to LET THE ENGINE IDLE for 5-10 MINUTES! That's all I had to do! Everything runs normal now (except for the stupid noises coming from the hatch and minor AC rattle
)So, when you change or disconnect the battery, be sure that the first time you start the engine you let your car sit and idle for 5-10 minutes. The computer has to learn the new idle. Sorry if this is obvious to everyone else on this board, but I had no clue. I mean the manual says not to let your car idle when you warm up the engine...Before you look at your throttle body, spark plugs, engine mounts, or whatever, be sure you've done this, especially when you don't have 100k miles or more.
Good luck. Hopefully it's as simple as my solution was. I'm going to repost this around since it was such an idiotic revelation.
Scion TC 2006 stock.
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