I have a resonance that starts around 1600-1700 RPM and carries through the rest of the range when under load. No load no resonance. It sounds like it's coming from the driver's side of the engine compartment but then again, this may be just because I'm sitting there.

Anyone ever heard of this? Any ideas on what it is? Took it into ford to have it look at a few times and they said NPF. The last time they said it was my aftermarket exhaust.

I KNOW it's not the exhaust cause it was doing this before I put that on.

Any ideas would be appreciated.

 

Describe your problem more, i dont understand...

 

When I apply throttle and I hit about 1600-2000 rpm the car starts to resonate quite loudly from what sounds like in front of the driver. This continues through the rest of the RPM range but seems to quiet down a tad (maybe it's the exhaust drowning it out). THE ENGINE MUST BE UNDER LOAD. I get nothing when it's not.

Understandibly, this makes it hard to trackdown and pinpoint.

It am starting to be able to feel it I think in the pedals and driver's side floor slightly. I'm not positive that's what it is but I seem to only feel it when that resonance is going on.

It was quite bad just a few minutes ago when I dropped my brother off at his house. When I finally parked and got out there was a bad smell, almost like burnt plastic/electronics coming from under the driverside wheel well. I couldn't track it down though.

 

If you're getting a "burnt" smell you really should seriously look into the issue and don't disregard it as an "annoyance" Odd smells from cars almost always mean something is wrong and rapidly failing.
Resonation can be caused by zillions of things. The exhaust is the ususal culprit, but if you claim it was doing this before look at what you didn't replace(unless you replaced headers and pipes also, the whole shebang). Check the muffler,catcon, headers. Since it only occurs under load one of those is almost certianly the problem.

My '93 does that also, but it starts around 2000, and stops at about 2300 only when under load. Above that, it's normal, below, you can barely hear it. But I'm also missing my exhaust from the catcon back, so that might explain it.

 

Yeah, I'm taking it in tomorrow morning.

The strange part is it was doing it with the stock exhaust. It gets louder after you let the truck run for a bit and get nice and warm.

 

If it gets worse with heat the cat/con could be culprit, it's really the only component that changes(other than slight expansion) with heat. I don't know if it can cause resonance, and I have no way to check it. Some people mention the "BFH" and "broom handle" method for catcon issues. Translation, stick a broom handle in the end, mash it with a big f*cking hammer, and scramble up the innards of it. It'll fix any flow restrictions it might be causing. I dunno if that has any side effects, but I've heard it mentioned here more than once.

 

I took it to the dealer this morning to get it looked at. They say everything is fine. Took two technicians for a road test one says "harmonics" the other says "everything's fine".

Asked to take a spin in a similiar model to verify for myself and was allowed to ride along and was unable to hear anything. They wouldn't let me drive it, I think they had just sold it.

Anyway, I got a friend of mine to drive mine with me in the passenger and I can't really hear it. Makes me wonder if it's a hear through feel type thing. It's this drone/hum sound that's very annoying.

What do I have to do for the cats... just run a broom through?