ok so i just got the car its a 94 z with a 383....well had it about two weeks and it started to do this...it starts banging out and cuttin out real bad like a spark plug miss or a fuel problem it back fires real bad when it starts to do this and gets worse the longer you drive....well i replaced the wires, fuel filter, plugs,and on monday i replaced the opti spark with a genuine ac delco one ran a little better for 3 days with a small miss then it started to get worse and worse, today started to die a few times im kinnda stumped what should i do or where should i go from here????

 

Do the plugs look ok?

Is the engine running rich? (carbon built up on plugs)

Might want to do a compression test to make sure you aren't losing compression somewhere before toying around with all the little things that can go wrong.

A lot of people on here will point out a lot of parts that can cause a engine to misbehave but after perusing this board for a few years the best thing to do is just start testing things to rule out possibilities.

-Compression Test
-Fuel Pressure Test
-Chech for codes
-Unhook the electrical connectors going to injectors one by one and see if anything changed (not sure on this process so double check before you do it)
-Does your valve train need adjusting?

These are kind of the basics. Once you get it isolated it gets a lot easier

Hope this helps some.

 

unhooked the injectors one by one and it acted like none of the pass side made a difference....fuel at a idle is 50 lbs it wouldnt throw codes yesterday light just stayed on but my rockers might need to be ajusted but wouldnt it do it all the time???

 

Light just stayed on? If you are talking about your service engine light then you need to figure out what codes your car is throwing.

Hopefully someone can help you out with what it means if half of your injectors being pulled doesn't make a difference. I am not quite sure.

Still would recommend doing a compression test. You can waist a lot of time chasing gremlins when you might really just need a new head gasket or to have your heads looked at.

Good luck.

 

The vacuum gauge is great at checking the engines condition. If the vacuum stays at 15-20 your engine should be fine but if it goes all over the place you have problems and my Chilton has a break down of each type of change. I believe you can find out if you have a blown head gasket to a bad valve. $10 at Schucks and it also can be used for reading psi if you have forced induction.

 

could it be a bad o2 sensor i had similar problems what happens when its in open loop before it warms up is it ok to drive until normal operating temp?

 

yeah its ok to drive untill then and then it starts to screw up so i dunno.....when you put a paper clip in to jump codes the light just stays on and dosent flash????

 

get the car to autozone and get it scanned check the millivolts on the o2 sensors, if ur saying it dosent happen when its cold but when its warm it happens i think its the problem with ur o2 sensors because they kick in when the engine is in closed loop (normal operating temp) someone correct me if im wrong

get them checked out it could be a pinched or burnt o2 wire as well which happend to me