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Topic: "popping" in floorboard (Read 1776 times) previous topic - next topic

"popping" in floorboard

Got around to replacing the motor/transmission mounts and shocks yesterday but after starting it back up, my car is making this quick/rapid "popping" noise and it can be felt in the floorboard. It occurs whether in motion or not, but so far, reverse doesn't seem to do it. Park, neutral, and drive all do it. It seems to happen at the same rate whether its idling or cruising down the freeway...and not always with a consistent rate. It may miss a few beats.

If going down the freeway and I give it about half throttle (or hit "accel" on the cruise) it'll always do it, but once I let off and begin coasting (NOT "coast" on the cruise), it stops...until it receives a little throttle again.

Overlooked the underside and engine bay after the mounts were complete and everything APPEARED in place, but there may be something I overlooked that could have moved.

Solve for X
1988 Thunderbird Sport

"popping" in floorboard

Reply #1
possibly the new mounts are taller??  exhaust hitting the floor?
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"popping" in floorboard

Reply #2
okay, it IS happening in reverse also, when facing "uphill" (driveway). Exhaust looked good and was my initial thing to check. Whatever it is, its annoying and hard to find since it doesn't always happen
1988 Thunderbird Sport

"popping" in floorboard

Reply #3
I put the same exhaust back in my car when I redid my motor.  With the new mounts the right side header washiznitting the inner fenderwell.  Had to heat it with a torch and bend it and the H pipe in and down.  I'd always heard stories of header issues with old mounts not new ones.....
-- 05 Mustang GT-Whipplecharged !!
--87 5.0 Trick Flow Heads & Intake - Custom Cam - Many other goodies...3100Lbs...Low12's!

"popping" in floorboard

Reply #4
I'm gonna go out on a limb as I really know nothing about this type of thing but I'm gonna say maybe swaybar end links.  Mine did that but only when there was any kind of throttle at all, and it got much worse at throttle in turns.

"popping" in floorboard

Reply #5
I had a REALLY annoying rattle in my silver sprint, so I just installed a stereo to drown it out, worked for months :D

Does the sound happen when your not moving? that should rule out suspension problems, I had a broken front sway bar mount that rattled like hell, but only when driving.
1980 birds X 3, 1982 bird, 1984 XR7, 1988 TC

"popping" in floorboard

Reply #6
My converter washiznitting the floorpan in the 88. Looked like there was plenty of clearance but apperently there wasnt. Of course I had a bad motor mount and the trans xmember was rusting out.
85 Tbird 5.0
78 F150 351w
13 F150 4x4 3.5 Ecoboost

"popping" in floorboard

Reply #7
If your old mounts collapsed and you had an exhaust mounted then when you put the new mounts in it brought it up into contact with the floor boards. Also go around and recheck the bolts on the mounts. They could have worked lose and need to be retightened again.
88 Thunderbird LX: 306, Edelbrock Performer heads, Comp 266HR cam, Edelbrock Performer RPM intake, bunch of other stuff.

"popping" in floorboard

Reply #8
had a place look at it (for free) and the only thing they could find wrong with the exhaust was something is banging around inside one of the lers (and I heard it myself). I don't quite see how that could cause a sound like this, and all of a sudden, but I guess its possible. They're warranted so I'll get the bad ler changed on Saturday and see how it goes.
1988 Thunderbird Sport

"popping" in floorboard

Reply #9
Something in a ler? I hope that's not part of your cat or something.
88 Thunderbird LX: 306, Edelbrock Performer heads, Comp 266HR cam, Edelbrock Performer RPM intake, bunch of other stuff.