IIRC the 3.7L V6 is a Chrysler design. It’s related to the 4.7L V8. Many Fords, mostly those with automatics and EEC-IV and EEC-V ECUs, won’t rev any higher than 4500 RPM whilst in Park or neutral.
The effectiveness of any mod depends on the particulars of the vehicle. What works for one engine in one car may not work for another broadly comparable engine in another. Some engines respond very well to ECU mods, some to intakes, some to exhaust, some to all of the above, some to none in particular. It depends on a lot of things, mainly how bad the stock part was.
If you’re going to ask a question like this, you should specify the make, model, year, and trim of your car. And in most cases you’d be better off taking your question to a brand or model-specific forum.
Good information,thanks,replies like this make this forum very interesting-Kevin
I suppose this is true,what I was really after was the fact that some of this stuff is " gilding the Lilly" in some cases,I spent close to $400 on my “Dakota” on intake and exhaust mods,with little discernible effect(engine too small,vehicle too heavy-only thing that helps it is its 3.92 gears,some designs were excellent from the get go(Chevy small block,Ford big six,Dodge Hemi,etc).It was sort of a reaction to these infomerrcial TV shows.I refer you back to my post about the V-6 Camaro-Kevin