Cold Start Noise

I have a 07 Dbl cab Trd when I go to start it in the morning it make a knocking sound on the passenger side for only a second . Then when Iam backing out of the drive the exhaust make a fluttering noise only when its cold and only when Iam backing up . I have taken it to two Toyota dealers
one said to use synthetic oil which I all ready do and one told me it was my tires , which I find that just out of the question since this truck has only 27000 miles on it and I have had it since it was new . I then went and call Toyota customer service and got a case number and ever thing and made another appointment which I had to ride with the head of service and the dam truck didn't do it for him . He told me that the exhaust on the Tacoma is so thin that you can some times here it in the cab well I think that is just bull shit when it makes the noise it is loud . I was wondering if anyone else is having the same problem?

 

I've had the same damn thing going on now and can't figure out what it is. I thought it was the air conditioning but does it with or without AC on cold starts.
Keep us posted on what Toyota says i'd love to figure out what it is and have them fix it.

 

is the sound coming from under the truck by any chance?? check the backing plates by the rotors, one could be bent a little and catching on something, and also, maybe check the airbox, something could be loose around that side and hitting against something. let us know what you find.

 

but if something was catching on the backing plates or something was loose wouldn't it be on all starts and not just cold starts...
i'll try to take a vid of it tomorrow so yall can hear it

 

hard to really tell man. hope you get if figured out pretty oon.

 

Mine does the same thing, so this morning (4 degress) i found that the top plastic engine cover that says vtti on it rattles on the left if your looking at the engine, almost right where the airfilter is, just tap on the cover and you can make the noise, once it warms up the plastic doesnt vibrate a bad. I took some sticky weather stripping and installed it on the intake plentum and hoping this fixes the noise. Also where the air box intake tube goes into the pass. side fender it hits and vibrates a bit, so i took a small hose and cut it the long way and installed it on the fender all around the round opening in the fender.

 

Cold weather seems to create more noise problems. Maybe its just a seasonal thing? Once it warms up it will go away and then come next winter just expect it.

 

Since its cold, it could just be the short time it takes for oil to get to the lifters, valves, etc. I have an old Mercury that does this no matter how warm.cold it is. It was common back then. I wouldn't worry about it.

 

Its not an engine problem, its a vibration between plastic and plastic on the engince cover and plastic on metal where the air intake goes into the fender, fixed min 2 days ago and its quiet now. Its been 0 degrees for the last few mornings and no more vibration.