Hey,
Thanks for coming as I have a bit of a problem.
Recently I noticed my gas mileage has been going down drastically with about 9-10mpg at this point. It is as if I am driving a hummer.

The main problem began when my mounts broke back in early september. I purchased place racing motor mounts for my 2000 maxima gxe that originally had electrical mounts. These new PR mounts created a lot of vibration when idle, but I kept them since they produced no wheelhop what so ever.

Well, my check engine light came on like a week later with the error, high idle speed. My mechanic said it was just a dirty manifold and attempted to clean it with some carb cleaner. Reset the computer. 2 days later, same code, same error.

I noticed that the rpm that it keeps during idle is never less than 900 when in Parking or Neutral. It is around 700 while in drive. Once I release the brake, the car drives as if i am gassing it at 1000rpm.

I got scared and took the car to nissan to schedule a date to check it out. This was today. Here is what they told me:

The motor mounts that you have are not orignal. THe original mounts had a built in sensor that communicated your ecu. Now your AC valve is malfunctioning and your ecu has a problem. This high rpm have also gotten your Cat convertor cloged. All parts and labour will cost 2000.00 to fix.

I almost cried, I am a full time student that works just to pay for insurance and gas while hooking the car up little by little.

I called up cattman with my complaint, but they were nice. Got one of their techs to call me back, explain the design to me as well as assured me that since thousands of these mounts were sold, I was first with aproblem like this and he did not believe the mounts had anything to do with it.

What the heck should I do, I am already getting ready to sell my car as I am so $%)$@$% confused. All comments and suggestions would be greatly appreciated.

 

anyone?
bump.

 

Wrong place man...no one here can and will answer questions like these man(atleast some won't)...the only thing that goes on this forum is how to boost your car!!!

Sorry I dont know why either...

 

High idle, poor MPG -- I'm old school (carbs and points, baby) and would suspect vacuum leak or poor mixture in such cases, but for these new engines...

-- MPG problem: start with the MAF. If your MAF is shot the engine might be dumping excess fuel into the cylinders. Also perform ECU Reset and Idle Air Volume Learning procedures, look on the .org for posts on these subjects.

-- Fast idle problem: Check the IAC motor/idle air bypass valve (not sure whatNissan calls it) on the throttle body. Your mechanic may have gummed it up with junk when he used carb cleaner on the manifold/tb assembly, causing it to stick open a bit (would cause high idle.) Do the Idle Air Volume Learning procedure as above.

-- Not the MAF/IAC (bypass valve)? With the engine running, spray carb cleaner around the intake manifold and throttle body (not INTO the throttle body) and on the vacuum hoses coming out of the TB area -- if the engine starts to rev up you have a vacuum leak there, or an intake manifold gasket leak.

I don't know anything about nissan's "electronic" motor mounts, but I wouldn't think, they would affect your car's idle.