Hello there, I'm having some issues with my 1996 Mazda MX3 1.6L 5-speed. I'll begin by listing the symptoms/issues my car is having, followed by what I've done to try and solve these issues.

Symptoms/Issues:
1) RPM's dropping to about 200-300: sometimes even lower almost causing the car to stall (oil/engine lights come on like it's stalled, but engine revs back up) and even occasionally stalling completely. This typically happens when coming to a stop and pressing the clutch in. Also it typically happens after the car has warmed up.

2) Rough idle: After the RPM's drop down to that low range (200-300ish) they'll usually jump back up to about 700(ish) which is a bit low compared to what my normal idle RPM's should be.

3) "Pulling" while driving: I notice this most frequently in 3rd gear while going a constant speed (not accelerating) the car feels as if it's pulling or jolting forward, and as soon as I put some pressure on the gas this usually goes away.

4) Whistling sound: I can hear a faint whistling sound from under the hood, it's not very loud and most noticeable right after starting the car.

5) Power not going to wheels: This symptom doesn't happen as often as the others but sometimes I feel as if even though I'm accelerating the power isn't going to the wheels right away, instead there is a slight hesitation before the power goes to them.

Things I have done:
1) Removed and cleaned the throttle body
2) Removed and cleaned the IAC (Idle Air Control valve)
3) Replaced the O2 sensors

Other Notes:
-After some research I read that the cause of this could be a vacuum leak, and when checking under the hood I noticed my air intake hose had a crack in it, which has since been repaired.

-After replacing the O2 sensors the issues did seem to disappear for a few days, but since then have returned.

-My car isn't throwing any codes

I'm hoping someone here might have some insight/suggestions on what I should check/be looking for as the cause of my issues. And if you need any additional information, I'll be checking this post frequently and can provide it.

Thanks in Advance,
Mark

 

Mark:
Good catch with the cracked air intake hose. You may still have a few more vacuum leaks. Use some MAF sensor cleaner and spray it everywhere around the intake while you listen for the engine noises. When the idle gets temporarily better then your spray is being sucked through a leaky area.
Did you replace the plugs, wires, rotor cap and rotor?
how is compression?

Get more ideas here: https://www.mazdaforum.com/forum/maz...g%C3%A9-31136/
Pretty much everything applies to your engine as it is the same drive train as the Protege.

Good luck!

 

I found another cracked hose when I found the first vacuum leak both have been replaced, I'm going to use a section of a garden hose as a makeshift stethoscope and see if there are any other leaks.

I'll try the MAF sensor cleaner.

I have not replaced the plugs, wires, rotor cap or rotor just cleaned.

I was curious as to if it could be a clutch issue as I've noticed my clutch isn't engaging quite as "strong" as it did in the past (if that makes sense) and it engages at the last 2ish inches of letting the pedal out.

 

You mean the clutch does not grip as firm as it used to...

As long as it does not slip the clutch is o.k. The pedal play can be adjusted under the hood where the cable goes to the bell housing.
If it is a hydraulic clutch you should replace the fluid and bleed out air bubbles like you do with the brakes. In that case the pedal play is adjusted at the push rod under the pedal. With around 2 " of play I wouldn't do a thing.
I believe normal free play is about 1 ". Free play is: from pedal all out until you feel resistance from the clutch. use your hand, not your feet to feel it out.

A clarification of terms: The clutch is "engaged" when the pedal is pressed all the way. It is "disengaged" when the pedal is out. Just the opposite of what I used to think. I avoid these terms when posting. Too many people get confused.

Things I would do: replace the ignition parts and clean out the EGR Valve and EGR passages. Also follow the vacuum line that goes down behind the intake manifold, pull it off the nipple at the manifold and push in that nipple with a wire. Push through any resistance.

 

I agree with tanprotege with checking the compression, cleaning the MAF sensor, and checking for vacuum leaks.

But let me suggest taking a look at the VRIS or whatever its called on the 1.6L, there is a solenoid that opens and shuts a butterfly valve on the intake. Might be sticking, malfunctioning, or inop.

I also agree with tanprotege on the clutch, bleed it

Whistling sound? Sounds like the car wants you to find the vacuum leak, which it sounds like you have.