hey guys i have a 96 miata with about 121k miles...just recently noticed a knocking sound from the engine...i had this sound before only on startup and it would go away in 3 seconds after starting...but now its not going away...oil changes before were 10w 30 and i am still using the same oil...just did a oil change too...any ideas would be appreciated..thanks![/align]

 

Lifters make a clicking sound but you say a knock so if it progressively got worse it could be a main/rod bearing. The a/c bracket also had a nasty habit of losing the bolts that hold it to the block and knocking. Hard to say without hearing it but you can isolate a rod knock by removing each plug wire one at a time. If the knock goes away when one is removed but not the others then it would be a rod bearing on that cylinder. The crankshaft keyway was famous for wallering out but usually shows up as power loss not a knock. You can watch the front crank pulley/damper and see if it wobbles.

 

Hmm, but it is normal to hear some lifter ticking? My Z3 does it when I autocross it from a bit of oil starvation (the lifters get noisey when they get foamy oil) and it normally goes away. My dad's truck does it all the time (and has done so for the past 3 years) but it also makes all sorts of other nasty sounds that make me care less about the lifter tick lol.

 

Does it sound like a diesel engine? If so, turn on/off your a-c. If it comes on when you turn the a-c on, the it's your compressor. If it sound like a 'light' tapping noise, you need to get your lifters checked. If it's a deep growl of a noise from the bottom of the car (check when the car is on), it's usually your crankshaft (journals need to be checked). Hope this helps (got this from experience and friends).

 

Hello to all. I am new to the forum, I recently bought a 97 Miata 1.8 F.I.with 127k and it ran beautifully for couple of weeks and is now getting progressivly worse in the same dept. It runs ok until it warms up, then starts to act like it has bronchitis(heavy hesitation and not an affliction forthe ford vehicle) at around the 2-3k prm range. this is scaring the crap out of me as I haven't even made a payment yet and it was fine when the mech looked at it before I bought it. could I have the same problem? F.I.?, fuel filter?, plug wires?, what should I replace first? they all look like they are in good condition and the O2 sensors were recently replaced? HELP.