I had just recently purchased a 1986 mazda rx7 and suddenly the cars throttle is not being responsive.. when being push at full throttle it would react late, and the sensors have been checked and all of them seem to be fine, so now i;m working on the fuel system and while trying to figure out the fuel system, the car suddenly cant stay @ idle...? i am like going downhill just trying to fix one thing and something new just keeps popping up, need help or assistant on where to start.

 

The first check is compression, this sounds like a bad rotor. The engine will run, but will be slow to respond and will not idle well. Do a search for compression check on this site.

You could also just remove both spark wires to each rotor in turn, this should nearly stall the engine if it is good, if bad, removing one set will make no difference, while removing the other will make the engine stop cold.

I personally recommend a compression check. (You can get a guage for $20-$30 at any auto parts store, simply remove the check valve in the end, thread it in and watch it while a friend cranks the car with the gas on the floor. You should see three even bounces over 90 psi. The EGI fuse should be removed while you do this.

 

my compression is fine, i had taken it to a shop and it all checked out good, they also checked all my sensor, and they thought that it could be my BAC, or either my whole intake manifold need to be clean, but in my mind that was weired because how can a car run so good and suddenly just be bad the next day.. which is really weired, so i did some research and found out that it could be something in my fuel system.. or either my cat could just be clogged, because the car does seem to have no back pressure and some smoke comes from my shifter comming from my piping, it smells like dried up oil but its comming right under neath the shifter..? what does that mean if its comming from underneath the shifter..