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Hi all, ive just bought a Mazda MX-3 1.8i V6 K8 '95.

Ive been driving it for a week now and seem to be using alot of petrol, i thought it was designed to be more fuel efficant than this!?! Also when it idles it shakes like a drug abuser on re-hab! ive poped the bonnet and the engine is in great condition except a few cogs here an there which are a little rusty round and squeek a little but seem ok. An when and only when its moving there seems to be a thumping coming from the engine but its fine when its not moving?? im pretty sure its not ment to do that? this is my first V6 and ive taken friend out in it an he says it sounds normal!?! am i just being picky!?!

K lemme see if i can touch all the bases here for ya.

First, if your car is an auto you should be averaging about 200 miles (convert to KM) per TANK. Manuals do better but our engine isnt as efficient as one would expect.

The idling issue could possibly just be a hairline crack in the black tube that connects to your throttle body. The ribbed section commonly is the culprit. Try taping it with duct tape. If that doesnt have an effect you may have to adjust the idle screw that sits on top of the TB. Allow your car to rev higher and the shaking will go away.

Lastly, the thumping sound you hear when driving is most likely a wheel bearing/ ball joint/axle/ cv issue, again all are very common in our cars

Idle speed in neutral should be 650 to 710 rpm.

I was thinking it might be a bad motor mount....the issue with the car shaking like crazy at idle. My 626 has a torn mount right, now and it shakes like a mother right now for a 4 year old family car.

Turns out it was the wheel bearing on the drivers side, it was totaly smashed up! lol supprised i didnt dammage the hub!


Anyways had a look into the virbation and low idle fault, the garage plugged some cables into the car and did a self diag, turns out theres a fault #16 EGR fault.

The guys looking into whats causing it. any of you guys heard of this??

If it's an EGR fault, it may be a bad or disconnected vaccum hose????

How hard is that to fix? could a noob like me do it?

Originally posted by cowwilly:
How hard is that to fix? could a noob like me do it?

Replacing a vacuum hose is easy as cake. It's diagnosing which one is bad that's hard. There are so many, it's hard to know which one is bad, if any.

Well it turns out it was just the HT Leads, stupid thing was i had them changed 2 or 3 months ago! Anyways theyve changed them and its running sweet as a nut!

Cheers for your help guys.

Just curious as to what HT leads are? The different terminology for parts from other countries throws me off.

Originally posted by TsiMiata:
Just curious as to what HT leads are? The different terminology for parts from other countries throws me off.

Its oldspeak for the plug leads and coil secondary. The wiring on the primary side of the coil is Low Tension (LT), and (you guessed it) on the secondary side, High Tension (HT). Tension is a quaint old way of saying voltage.

I seem to be having sort of the same problem.. about that black tube would taping the hell out of that help if there was possibly a hairline fracture?

Try Silicone wrap/tape, almost looks like electric tape, it works great.