That's cool Nathan and about the same price as the stealer sender <img src="/forums/images/graemlins/kewl.gif" alt="" />. So does your gauge move rapidly with changes in engine speed/load? I wonder if you could use the original gauge and just replace the sender with one that gives you 'real' readings.

It does move pretty rapid with engine speed. I'm not sure if you could use the original gauge because I would assume that the sender/gauge combo would need to be a match set.

I only had an idiot light to begin with, and found out the hard way that the light will only work if the wire is hooked up to the sender <img src="/forums/images/graemlins/shiner.gif" alt="" />.

An engine rebuild later, I vowed to have a real gauge. <img src="/forums/images/graemlins/kewl.gif" alt="" />

Not always. Different car, but same problem and as you can see from this just a sender can be used sometimes. I'm not saying that there's anything wrong with what you did Nathan, it's just interesting. I have a '92 Miata (<img src="/forums/images/graemlins/ignore.gif" alt="" />) which has a real gauge and that thing jumps up and down WITH the tach <img src="/forums/images/graemlins/kewl.gif" alt="" />

I think that article proves my point. The sender only gave that guy a moving gauge. It wasn't calibrated to any specific value. He had to modify the circuit with a resistor to improve it.

That's the reason why you can't necessarily mix and match any sender and gauge that you want off the shelf.

I agree. I was just interested in the idea of having a more accurate reading while retaining the stock gauge. <img src="/forums/images/graemlins/kewl.gif" alt="" />

I'd have to check my FSM about your fast idle set-up on a 3.5 liter engine. The way the older 3.0's work like mine is this, there is a fast idle valve at the bottom of the throttle housing. Bolts to the bottom of the throttle actually. It's coolant temp controlled if I'm not mistaken. <img src="/forums/images/graemlins/notooth.gif" alt="" /> The valve when cold should be open to allow more air to bypass, which gives you a higher cold idle . Then, as the coolant heats up from the engine running, it slowly closes, and your idle drops down. The stepper motor, which is just above this valve takes over idle duties at all other times. Make sure your engine coolant temp sensor is working as well. For a 3.0 liter 12 valve engine, it plays a huge role in keeping the stepper motor control by the engine ecu accurate. Mitsu's number 1 check when using the FSM for idle instability is to check the NTC or coolant temp sensor. Usually if it's this bad you'll set an intermittent Check Engine light as it moves in and out of specs. For a 3.0 liter, you get fault code 21, probably a different code on the 3.5 liter engine like you have. I'll check the FSM tonight if someone else doesn't have more/better 3.5 liter info for you.
You may only need a gentle cleaning of the stepper motor and the section of the throttle that it sits in.

Thank you very much for your replay Houston. Last time I changed the spark-plugs I noticed that all the plenum was full of a black layer in the inside like Burned oil and also the throttle body so maybe this valve maid be stacked from that dirt. I will checked it this weekend. Tank you very much.