Question about clogged cat
 

Would a clogged cat make my car backfire while driving and at idle?

actually a clogged cat would actually make your car run like crap, even at idle ,specially under acceleration....If you could borrow a back pressure tester gauge from somebody you could get that possibility out of the way....Its easy to test..if you need any help let me know...

Timing off can do it. An exhaust leak can do it. A sticking open injector can do it (raw gas down the exhaust).

it idles fine just back fires a little. But it does run like crap its a 5 speed and when i start to move the car starts bucking (and i no how 2 drive standerd). its does that till like 2000 rpm then it runs a little better but then after that it runs like shit agian. It back fires when im driveing to. But it does have an exhaust leak it needs an exaust pipe gasket but i dont think it would make it run this bad. Ill be going down the street then floor it and it will speed up but harrably. it cant be spark plug (irridium) or the plug wires becasue there where just changed recently.

Im ganna try and test the back pressure. what should it be?

Well now you have given us more info. runs poorly, not just backfiring.

If its N/A, Cap & Rotor = replace !

Misfiring is your problem. Why is the question. Could be a lean fuel condition.

How could i tell if its a lean fuel condion? and what should i do?

if u get your hands on a backpressure tester ,hook it up on the o2 sensor orifice before the cat. I cant remember but it should be in the low 0 to maybe 3, cant remember but it pretty much should be steady on the verry low also during acceleration, there should not be much fluctuation on the gauge under accel..

First do a tune up! Plugs, wires, cap and rotor. Most of the time that is all it is. If you have a cylinder or two that aren't firing, it will have no power and buck and backfire. Try that simple stuff first then see how it runs. Air filter too.


Russ

is your car throwing any codes (engine light is on)?

if not then I agree, do cap and rotor, check your timing, check all your vacuum hoses for cracks or missing connection, replace your fuel filter, and perhaps test your fuel pressure.

if you still cant solve the issue, sometimes its nice to take it to a mechanic for a scope check. Its usually a reasonable fee and a good mechanic can usually figure out whats wrong for you. Then you can do the work yourself to save money.

Anyway, just a suggestion

no codes but i think i narowed it to a boost leak and it must be giving my car to much gas and not enough air because the air goes in the MAF then most of the air must come out some where on the way from the turbo to the intake manifold. But would it make my car flutter or wanna stall when i get on it or start moving? i got it up 2 around 5-6 rpm and the boost only goes to 4-5 psi