Rumble when cold? Lend me a hand fellas :-)

[serialtoon]

Ok, so in the morning on my way to work, when the car is cold i kind of feel like the idle might not be as good as when the car has been on for a while. Now, this is obvious, but sometimes i feel like the car is slightly hesitating on say, a stop light, while i wait for it to turn green. Its more like i can feel the exhaust almost "coughing" if you will. Its very slight and you dont hear it much, but its enough for me to feel "something". Its not a huge problem cause it only does it in the early morning (7am). Once the car is warmed up, it wont do it anymore for the rest of the day. Ive had the latest TSB (fuel pump) done a while ago and everything is running normal. I have a Cobb SRI thats all, everything else is stock. Anyone get a feeling like this? Thanx!

 

[Zeya]

There is a TSB out that addresses this exact problem. If you don't know what a TSB is, it's a document that is sent to mazda technicians at every dealership that describes symptoms of a problem and how to address it. You're describing one of the symptoms in the latest TSB. Do a search on "TSB" or "fuel pump" and you'll find a discussion of it. You should definitely get the service done. They'll probably replace your fuel pump and/or reflash your ECU, depending on your VIN number.

 

[Zeya]

Here's a link to the TSB. Give it a read.
http://www.mrlilguycdfps.com/random/4208HPFP_TSB.pdf

 

[serialtoon]

There is a TSB out that addresses this exact problem. If you don't know what a TSB is, it's a document that is sent to mazda technicians at every dealership that describes symptoms of a problem and how to address it. You're describing one of the symptoms in the latest TSB. Do a search on "TSB" or "fuel pump" and you'll find a discussion of it. You should definitely get the service done. They'll probably replace your fuel pump and/or reflash your ECU, depending on your VIN number.

No meaning to be a jerk, but i specifically stated RECENT TSB DONE on my car So no, its not that. But thanks!(uhm)

 

[Zeya]

No meaning to be a jerk, but i specifically stated RECENT TSB DONE on my car So no, its not that. But thanks!(uhm)

You're right dude. I totally just read the first two sentences of your original post and skimmed the rest. I need to make a point of reading entire posts before responding. Sorry about that.

 

[Speedy3]

How long do you let your car warm up? It may not be related, but the engine will run a little rough if it's not up to operating temperature. The block is still cold, so therefore it is quenching the heat in the cylinders until everything warms up. You need the heat in the cylinder to get the most efficient burn. I always let my car warm up until at least the needle has moved 2 notches. Usually about 4-5 minutes.

 

[Speedy3]

Oh, and by the way, you may have fouled or cracked plugs if it feels like it "stutters" on acceleration. Usually, these symptoms of cracked plugs goes away when the engine heat is hot enough to support a weaker spark. If you feel inclined to check the plugs, do not try and clean them or gap them, just inspect them. Gapping or cleaning them can cause cracks too.