All this happens once in a while, not everytime. Every couple of days I will try to start my car and it just spins over, doesnt even try to start, I turn the key off and try it again and it starts right up, sometimes missing like its running on 6 or 7 cylinders but clears up after a few seconds and smells really bad.
Problem number 2. Sometimes when accelerating fairly hard it feels like it dies and then starts back fireing through the exhaust and blowing black smoke out the exhaust, if I let off the gas it will usually return to a slow idle and sound good until I try to go again then it does the same thing. If I turn the key off and restart it it is usually good to go again.
The car has 250000 miles on it, I replaced the opti at 80000 and also the MAF and plug wires at the same time, nothing else has been changed except for spark plugs since then.
Any ideas? Also, any tricks to changing the opti, I cant remember anything about the last time I changed it (8 years ago).
Thanks.
Ron

 

I'd say do the usual: check plugs, wires, opti harness, coil wire for burns and corrosion.

If it is the opti again, its pretty straight forward. When I did mine, I was told to remove the fans, it's simple and frees up a lot of room.
-Remove the serpentine belt
-Unbolt and remove the harmonic balancer (you'll probably require a gear puller)
-Disconnect the hoses to the water pump
-Unbolt and remove the water pump
-Unbolt and remove the opti.
-You have the spline drive opti, I'm not familiar with installation of that so someone will chime in.
-Other than that, reversal of disassembly and you're good.
Be sure to use new gaskets and clean the gasket surfaces thoroughly for a tight seal.

Diagnosis is tough, you got a lot of miles.

 

car needs a tuneup. The black smoke sounds like your running rich which is probably because your wires and opti all have 170k on them. Or it could be that your water pump is leaking and is causing the opti to fail. Id be ready to spend about $600-$700 for an opti, waterpump, plugs, and wires.

 

Coil too, while you're at it.