2003 Mustang GT auto. 49,000 mi.
K&N FIPK - FRPP 4:10's - Nitto D/R's

I'm having a little engine trouble that I want to take of before I do any other modifications and I need some advice.

1 - There is a slight hesitation while accelerating, sort of a jerking motion, but only under slow acceleration (shifting at about 2,000 rpm). Also, it only happens in 3rd gear for some reason. Under hard acceleration, there seems to be no hesitation at all.

So I changed the spark plugs since it's cheap and easy hoping for results, but no luck.

2 - When I start the car in the morning before it warms up, there is a whistling sound when I rev the engine. After the engine warms up a little, maybe 5 min. or so, the noise is gone and doesn't happen again until I start the engine being completely cold, like the next day.

The mod's were put on only a few months ago, and these problems were there before them. Anyway, any advice on where to go frome here would be greatly appreicated.

 

Haven't checked it lately. I'll need to warm the engine and check it later on.

 

I've got a k&n fipk and mine whistles...

Open your hood and hit the throttle (look for your plenum, youll see it) Find the throttle body and then the throttle cable. Pull on the piece that the cable is attached to (not the cable itself!). Listen for the whistle. My guess is that its just your K&N filter. Put your ear near your filter and listen.

If its not that it could be a vacuum leak, but it wouldnt make too much sense especially if if doesnt seem like you are losing HP in 3rd gear at WOT.

 

I think you might be right about the filter.

Does yours whistle when the throttle is opening or as it's closing. Mine whistles as it's closing. Just want to make sure we're hearing the same noise.

 

Sounds like either a tranny problem or a bad coil pack causing a miss. Hard for me to tell from your post whether it's engine or drivetrain related.

 

When was the last time you changed the fluid? And does your car kinda buck in any shifts while normal driving?

 

Never changed the fluid. I've only owned the car for 3 months. It does buck a bit when shifting from 3rd to 4th. I guess I should have it changed to be on the safe side. I'm gonna go check the fluid level in a few minutes.

Does anyone elses K&N whistle, and if so, does it do it all the time or just when the engine is cold? I can't tell if it's the filter or not.

 

mine whistles when i put load on the engine or if i mash the throttle in netural....when i open it and close the throttle, it makes a whistling sound.....but only in certian rpms....and i have the K&N dropin

 

Take it to a transmission place like Cottsman Transmission or AAMCO....and if you decide to change the fluid make sure they drop the pan and change the filter. Then ask them to inspect it while they are at it.......

 

I checked the trans. fluid and its okay. I guess I'll bring it to get the fluid and filter changed. If that doesn't solve it, I'll put it in the shop.

 

Do you have a warranty?

 

Yes, I bought an extended warranty. I think I'm covered until 70,000 mi. It's not a manufacturer's warranty though so I don't know if it covers everything, but I'm gonna get it checked out after X-mas.