I just recently purchased a 2000 4.7 dakota quad cab and was curious about the idle jump, when I put the defroster on it appears to boost the idle between 500 and 800 more rpm I realize maybe its to compensate for the compressor but I have just never seen a vehicle jump that much and also I appear to be getting around 8.7 to 9.3 miles to the gal on gas is this average?flowmaster exhaust on it now no filter kit does anyone recommend this upgrade and if so what type the kn stock replacement or tube style?thanks.

 

No way dude before i put the charger on my truck i was getting almost 23 miles/gall on the hwy. The idle jump is not right you should definatly get that checked out that. does it have an electic fan on it? that may or may not be ur problem. good luck.

 

first of all, demondakota, i am dying to see some pics of your ride because it sounds like you have quite the truck. moving on to the questions at hand. should your rpms be jumping that significantly for turning on the defrost? no. is it only doing it when the motor is cold? try putting on the defrost on when you are at normal operating temp, or try putting your a/c on at normal operating temp and see if the problem still exists. as far as the gas milage, that just plain sucks. first things first, drop in a k&n filter and replace your distributor cap/rotor, spark plugs and wires. you should see at least a substantial difference in mpg right there. if not, then you have a bigger problem going on, or a lead foot and you are the only one who knows for sure.

just my $.02

 

when you add electrical load to your truck it makes the alternator harder to turn which slows down the speed of your engine, thats why your engine compensates and increases idle.

 

this is true, but a jump of 800 rpm is more than what you would usually expect.

 

Check out my last post on the PCM reflash and idle problem I experienced. It was the transducer that controlled the a/c.....since it was faulty I was getting very high rpms 3200 or so whenever the defroster was working.
https://dodgeforum.com/m_620136/tm.htm

 

tHANKS VIRUSED I AM GOING TO GET PICS ASAP I AM GETTING A PAINT JOB THROWN ON IT RIGHT NOW. AS SOON AS THAT IS DONE PICKS WILL BE UPDATED. BUT WITH THE PROBLEM AT HAND IT BEING SUCH A NEW MODEL DAKOTA IT DOES NOT HAVE A ROTOR CAP OR WIRES. IT HAS COIL PACKS AND THE ARE VERY EXPENSIVE. I HAD TO PURCHASE TWO FOR MY TRUCK DUE TO DAMAGE FROM ENGINE WORK. TREAT THEM VERY GENTLE CAUSE THEY ARE EXTREMLY FRAGILE.

 

I t will jump up idle even when the engine is warmor cold and the fan goes on almost everytime when first starting truck til I drive a bit ,the dealer says it's normal but I still don't believe them,I also noticed that I hear water bubbling noises inside the truck as you would here from baseboard heating in a house when it's cycling to heat up house, maybe I have a bad thermostat?can I unplug the a/c compressor to see if it changes the situation ,also wondering what's recommended for a filter the K&N stock replacement or the whole kit style is there that much of a performance difference versus the price? thanks again guys.