It's been a while since I posted here, but I was hoping to get some help from the T4R.org crew on something that has been bugging me for a few months now....
A few months ago, I began to notice that my '07 V8 4R would start to vibrate when I was sitting at a stop light. Normally my engine runs so smooth and quietly (even with 177k miles on it) I can hardly tell it is running. This is still the case when the car is in park and in neutral. However, once the engine is warmed up (it doesn't seem to be as prevalent when the engine is coming up to temp) and in gear while at a stop, the vibration begins. It's very noticeable at this point, but the car runs and drives great other than the vibration at a stop. No check engine light, either.
I changed my spark plugs last fall (coil packs still looked great), and cleaned the throttle body and MAF sensor while I was at it. I clean the Volant reusable air filter once a year as well. Everything was running fine at that point. After the vibration at idle in gear began, I visually checked vacuum lines but everything appears to be in good shape.
It sounds exactly like what happened to
@
NJshadow93
in the thread below. He stated that his shop eventually found a small exhaust leak due to a rusted bolt on a flange gasket. I've checked underneath my 4R multiple times, and I can't see, smell, or hear anything that would indicate I have an exhaust leak. I tried PM'ing NJshadow93 to see if he could be more specific on where the vibration originated, but he might not be active here anymore.
V8- Vibration in Gear at Idle - Toyota 4Runner Forum - Largest 4Runner Forum
The rough idle in gear began right around the time I had my alternator replaced at my shop (I can't remember for certain if it was before or after the alternator went south). I'm not suggesting that the alternator replacement is what caused it, but it's a data point none the less. I asked my shop about what I was experiencing, and they recommended to clean the throttle body again and give it a few days/couple hundred miles for the ECU to potentially relearn the mapping from the throttle body from having the battery disconnected during the alternator install. I did that but almost 2 months and hundreds of miles later, it feels the exact same. I stopped by my shop again for them to scan my ECU for any faults but it came back completely clean. I was almost hoping there would be a fault code so I could start looking in the right direction, but I'm just throwing spaghetti at the wall at this point hoping something sticks and I can fix the problem.
What am I missing?? Engine mounts? The PCV valve? Vacuum leak that isn't being detected by the ECU? I'm at a total loss here.
Any advice or recommendations on where to look next would be greatly appreciated.