I have an 07 GT and I noticed lately that when I am driving I hear a thump that seems to be coming from my struts. The thumping noise is slow when I am dring slow and it goes fast when I am driving at highway speed. Could it be that my struts are gone. I have lowered my car about 2 years ago using Steeda Springs. I think the drop is 1" front and 1 1/4 rear. I have replace also my tires to GY 255/40/17. But the thumping noise does not go away. Should I go ahead and replace my shocks and struts. I was thinking maybe, it is worng out prematurely due to my lowering springs. What do you guys and gals suggest I do next? Thank you in advance for your suggestions.
Also, I have two tunes in my car. The car drives fine when I'm using 86 tune. When I load my 93 tune of course after filling up with 93 gasoline, my car drives real rough and when I accelerate there is this rattling noise that seems to be coming from my exhaust pipes and muffler. Thanks, again.

 

cute.

 

If you're hearing a thumping that changes frequency with speed, then I suggest you check your tires for cupping or a flat spot. These can be caused by worn suspension parts. How many miles do you have on your car? However, you also state that you replaced the tires and it still thumps... Perhpas a wheel bearing? The thump has me stumped...

Whose tunes do you have? If it's not rattling with the other octane tune then I suspect you're getting engine knock. Have you tried fuel from a different gas station? Run that tank of 93 down to about 1/4 tank and refill with fresh fuel from somehwere else. If it still does it with one tune and not others, then you need to get in touch with your tuner and have him adjust your 93 tune.

 

I have 42,000 miles now. I am a lot worried now because the car is sitting much lower. I used to have enough clearance even with the lowering springs. But now it has gone so low. I don't even have 3" clearance from the side behind the front wheels. I am tempted to go back to my original springs. But that will look like a 4 X 4 again.