I did a search on this as wasn't able to find anything on this....but here it goes...

I noticed while my car was idling that i had it back firing as well.....i turned my lex off....waited a minute and turned it back on, and my lex was smooth again..... i thought it actually had something to do with the gaskets .....(had them changed) and it's a lot more quiet but behaves the same way....what do you guys think?

Check spark plug wires, distributor cap and rotorc Could also be some carbon buildup in the combustion chamber. Run some seafoam through the tank.

coo thanks the kid that owned this prior to me said that he has all new plugs and wires and cap (factory) ....but i'll re check em all.....just in case...what did you gap your plugs at? and i already seafoamed him up....(tank,brake booster hose, and oil crank case) when i first got him...i plan on doing it again very soon though as my next oil check is coming up...

.043inch or 1.1mm on the plug gap. If it all has been replaced it should be good for 60,000 miles. Doublecheck to make sure, also do a water flush or do the seafoam flush to get rid of any carbon built up. I'm assuming there is no engine light on in the dash?Has to be pretty simple! If you get new plugs (if the old ones electrodes are rounded) get irridiums.

Howmuch did your gasket change cost?

i had the same problem i just changed the grey pieace thats inside the distibutor cap i forgot the name of it , i also put new spark plugs and everything cleared up.