I have a 94 blazer with a 4.3 vortec engine, it is hard to start, and when it starts it bogs down and you can smell fumes from the exhaust, and the catalyct convertor shakes real bad, any suggestions on what it would be and how to fix it would be great, also i'm thinking it could be the 02 sensor but i'm not sure where to find it. thank you

 

I would start by checking for troublecodes, next I would check the fuel pressure. How long has it been since the last tune-up, is the air filter ok? If this has the cpi fuel system, they are noted for problems.

I guess it might be possible the exhaust is trying to clogg-up.

 

do you think it could be too much back pressure caused by a bad catalytic converter? if its like my 95 s10 there are 3 bolts in front of the cat which you can unbolt and the start and see if the problem goes away.... I would not recomend leaving it running for too long though. just idle and check it. If the problem goes away change the cat.

as far as where the O2 sensor it is just infront of the cat on the exaust or on the manifolds them selves.

You can unhook the idle air sensor(so the computer uses the default settings) see if thats the problem. It could be the Throttle Position Sensor as well. best thing to do is get the codes pulled and see if you can narrow it down that way.

 

been having problems with my 1995 s-10 blazer. Just replaced fuel pump and it appears to be running extremely rich. It appears that I am getting fuel in my oil as well. I haven't taken the air intake manifold off yet to see what is leaking. Its a "w" VIN code and I am wondering if there is anything else that would make this happen besides fuel lines or the injector unit being bad.

 

I ran my 4.3 vortex out of gas and it took a long time to get it to start, once it start ran fine, now if it dosnt start first crank it is hard starting and today it wouldnt start at all I replacesed spark plugs look bad. I have spark at the coil and at the plug. Tank shows 1/4 but I'm on a slit hill, can't tell if I'm getting gas , what do I need to do next

 

Car ran out of gas, after putting gas in took a lot of cranking to get it to start. Ran fine 1 week now it won't start at all