Need Miata Help

[seanittner]

Help...

The wife has a 1991 Miata. I took it out for a test drive today after she complained about lack of power and sure enough, it will not go above 4000 RPM. Foot to the floor and it stops accelerating when it gets to 4 grand, any gear, and I also note some pinging/detonation. The only way to get it up to a highway speed it time and shifting before you get to 4000 RPM. Once you get there, it will stay there, unless you come to a hill...then it slows down and you end up having to downshift.

Could it be that crank pulley issue? I am going to look at it some more in a little while, but thought I would send this out to the 100's of miata owners out there...

As always, any help is appreciated. I will post more if I find anything else...

[AlanB]

Sean, IMO the catalytic converter is probably bad if you cant see the nose pulley wiggling. I have seen the elements break loose and vibrate around. Eventually the newly shaped (and smaller) element rotates around and blocks exhaust flow. Symptoms exactly as you descibed, or worse (even lower RPMs).

AB

[rodhx]

Todd Greene was just talking today about his son's miata doing the same thing. The cat was the culprit.

[toddgreene]

+3 on the Cat.

[seanittner]

Thanks All ! I am thinking the same way as the interior of the car felt like the heat was on yesterday (assume overheating cat) and the exhaust does make a rattling noise that it did not used to make (assume pieces rattling around in the CAT)

Meinike here I come on Monday...

[seanittner]

Sean, IMO the catalytic converter is probably bad if you cant see the nose pulley wiggling. I have seen the elements break loose and vibrate around. Eventually the newly shaped (and smaller) element rotates around and blocks exhaust flow. Symptoms exactly as you described, or worse (even lower RPMs).

AB

Mr Branch SIR ! You are THE MAN. You had it nailed EXACTLY. I got it off today (actually did the work myself with the help of liquid wrench, impact wrench and a cut off wheel) and I soon as I did, it was obviously exactly as you described. The tail end of the converter was almost completely plugged by the contents of the cat.

I thank you SIR and everyone else for sending me down the right path and now off to order a new CAT to breath a longer life into the wife's car..

Sean