Ive been having a problem with my 93 delsol 1.5 it has a rough idle and then it starts to miss as the rpms drop, i did a complete tune up fuel pump, filter, spark plugs, wire, distr. cap and rotor and its still has a miss fire im thinking its either a vac. leak but i don't know where or low compression in that cylinder any ideas? its only in idle its drives great also the cylinder that has a miss is the 4th one the closest one to the timing belt Please help!!

 

check your timing. and check vacume leak from intake manifold gasket. throttle body gasket. iacv. tps and map sensor o rings/gasket. perform a compression test.
with 1.5 d series non vtec engine. the compression should be

8.5:1~9.5:1 compression: 170-210 psi per cylinder

 

is there any trick to checking for vac. leaks I just want to make sure I do it in a way so I don't miss anything? as for the compression test I will do that tomarrow I'm hoping that's not the problem cause would b a pain in the ***