what do plugged catalytic converters act like??

Dont know if my experience is too relavent to this problem, but years ago when I modding my first high miles motor(150K+) in my manual 93 Taurus SHO I had the same exact problems your having, it eventually got worse and worse till it wouldnt even start with a push start, I went over the whole car for weeks on end PCM, wiring, MAF, Chip, and finally out of all things the timing belt replacement fixed everything with a new tensioner since the factory one had let the timing slowly start slipping tooth by tooth.

Now I know the 302's run a metal chain, but after lots of miles are they known to slip?

BadAndy said:

thank you sooo much!!! I was thinking i had heard that once before but was not shure , it is a 95 GT -5-speed, I wonder if i could fix it with a 95 GT AOD computer???

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The U4 (AODE) computer is just as bad (worse IMHO) in terms of tune. And FWIW, the puter (remember, '94+ have electronic automatic trannies) bogs when it knows to shift, so if you run one in a manual trans car, the car will randomly bog down (when it thinks it should shift).
That's yet another difference in the fox and 94-95 Automatic trans computers (A fox auto puter [A9P] works well with a T5); your idea would have been feasible if you had a fox.

My take on the ping thing: the 5.0L was an inherantly dirty (emissions-wise) engine. The factory 94-95 tune (too much timing and too little fuel) was an attempt to clean the emissions up. That's why people say the 94-95 computers suck. The computers dont suck (the processors are superior to the fox processors in terms of speed and function) but the factory tune is what blows.

Because of the relatively limited numbers of 94-95 Snakes, the Cobra processor was loaded with a decent, non-ping prone tune. This is a reason a lot of the TwEECer guys love the J (cobra) file as a starting point. It's also why the PIH conversion kits were so popular at one time.

I believe that Grady has posted info and specs on the T4/U4 processor with regards to fuel and timing curves (it might be on his website too) if you're curious.

As far as fixes, obviously a tune or handheld tuner would really help. Making sure the IAT, ECT and MAF are clean and calibrated can help. A lot of the guys like to run Top-end cleaner (a la Seafoam) and have good things to say. I'm kinda spooked by the top-end cleaners so I havent seen the great things that others report. A slightly colder plug can help (I run Autolite 24's in my '94). And little things like getting the fan on sooner (waiting till 208*F for low speed and 228*F for high is rediculous and certainly does not help keep pinging away).

Anyhow, you most definately are not alone. I really do chalk it mostly up to the factory tune however. I know it drives me nuts.

Good luck Andy.

I put cats on my carbureted mustang to make it pass emissions(No other emissions parts, only cats). I passed, drove around for a day or so, then my car started to sputter really bad. Would bog and hesitate/sputter BADLY when going from a stop or accelerating. I made it home and smelled something bad. Looked underneath the car and the cat was Red and smoking. Clogged up and heated up like crazy.