why it was so slow......
 

Took my car to my mechanic today, to see what was wrong with it. He replaced the fuel filter, and I replaced both the 02 sensors. The sensors were factory original with 140k, and the fuel filter was clogged but that wasnt the entire problem. Both the banks were running really lean, so i think and my mechanic agreed on the fact that the catless x pipe is what is messing it up for the most part. All the back pressure is gone, and the computer doesn't know what to do. Would a chip fix this problem, and with the catlless x pipe is my peak rpm lower now? My mechanic said putting a supercharger on it would fix the backpressure problem because it would raise the compression quite a bit, but thats a couple months down the road :D

RE: why it was so slow......
 

the catless x pipe should make the car run richer if anything but since you do have a 94 computer in the car which is a piece of crap computer doesnt help either so switching to a A9L computer will help a lot down the future too

RE: why it was so slow......
 

well he hooked it up to the diagnostic computer, and both banks were running way lean. Let's put it this way the car is now slower with 3:73s, a catless x pipe, and a CAI, than when it just had a catback.

RE: why it was so slow......
 

check for vaccum leak, check for tubing to be off before tb and after maf and check to make sure maf is clean. these are common problems. truck did this not to long ago. my air tube was off the tb

RE: why it was so slow......
 

that was actually the other diagnostic computer reading, it said the maf was reading the wrong amount of air or something.

RE: why it was so slow......
 

ok well your mechanic sounds like a dumb ass he told you that your car needs a supercharger so you take it to him and he puts it on, if the maf is sending the wrong signal that is why the car is lean, try cleaning the maf, also if your car still has the smog equipment then their could be something wrong with that, the smog pump pumps air into the back of the head but their is a valve that will let air into the atmosphere or puts it into the head to lean the car out, it sounds like that valve is staying open, i dont see why a x pipe would make the car that much slower, i think your mechanic is full of BS

RE: why it was so slow......
 

can you just unplug the smog pump, leave it in the car, and plug it back in when smog time comes in june 07? The smog pump has been making lots of noise for a long time, could very well be bad...

RE: why it was so slow......
 

yep it could be bad, i guess you can take the hose off but the sensor that controls the valve is only $25 i think, i had to replace mine

RE: why it was so slow......
 

do you know what the smog pump is called in the mustang manual(im guessing it's the air pump), it doesnt even list it. Oh and what is that sensor called?

RE: why it was so slow......
 

check for vacuum leaks or as someone stsated a sticking egr valve. The smog pump shouldn't make the car run any worse nor should the catless exhaust. What kind of O2 sensors were put in?

P.S. a fox computer is NOT better than a 94-95 computer, which is faster and based on load not rpms. B/C some A9L ppl were able to make h/c/i changes w/o idle problems while some 94-95 ppl were not able to, gave it a bad rep. The 94-95 comp. is a more efficient comp than an A9L. You can tune a carb car faster and easier than a fuel injected car. Does that mean that carbs are more efficient than fuel injection. If so, why aren't they used for new cars anymore? But this computer thing is a different thread!