My miata will sputters & lose power occasionally going uphill. I've been told to change the fuel filters & O2 sensor. Does this sound right? and how hard is it to change? Thanks for helping!

 

the fuel filter depends on the year. some years have the pump and the filter integrated inside of the tank. some of them, mainly the older ones, have the filter in line. the O2 sensors are not hard to change at all.

 

Yesterday it coughed & sputtered now today it ran like a champ! My miata is a '94....is there a guide to show me how to change these? Thanks again for all your help & knowledge!!!

 

I think is quite unlikely that the oxygen sensors are going to make the engine sputter and cough going up a hill. Fuel filter maybe but a clogged fuel filter will often just give you a feeling of power loss without the sputtering you describe.
Would be much more suspect of the spark plugs and plug wires as a cause of your problem as this is very common on the Miata. When going up a hill you are putting the ignition system and the maximum load and will be most likely to act up. Good test of the ignition system is to take off as you normally would from a stop but instead of shifting into 2nd gear, put it in 4th or 5th instead and then floor the throttle. You should feel quite a bit of power loss but should be smooth. If you feel a jerking type of sensation then the ignition system (ie plug and plug wires and possibly a coil) would be very suspect. The reason for this is that by doing this shifting into high gear thing you are putting a huge load on the ignition system but a very small load on the fuel delivery system.

 

What kind of plugs & plug wires do you recommend for a '94 Miata? Thanks for your help!

 

I agree with babyhuey.....I'd start with plugs/wires.....although if you suspect it still has the original fuel filter (you'd be amazed at how few people change these), it's not a bad idea to change that as well before you have trouble. They're only a few bucks.

I've had good luck with Accel and MSD wires, if you've got a radio you want wires with some kind of RF suppression. I like Champion & NGK plugs myself, but realistically just about any brand will work so long as you gap it properly. Local autoparts store (Murray's or whoever) can find the exact application needed for your car. If the engine is stock, I'd just stick with what they recommend.

If you want to work on it yourself (a wise idea in my book), I'd suggest getting a Chilton's or Haynes repair manual for your car. They aren't as detailed as the factory manuals, but I find they get the job done for a vast majority of the tasks.

 

MR heuy, I have posted this (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. ) on two (now three) places on this site and your diagnosis seems to make the most sense. will it hurt the car to drive it the few more days until I can buy the parts or should I park it until I can replace them? it does seem to be getting progressivly worse as I go along (reminds me of what happens when you rub a pencil on the inside of a distributor cap) but only at the rpm range noted. I will await you reply but maybe park it anywhoo just in case> wish me luck and I look forward to your reply.