95 Blazer runs poor

[brizzo123]

Hey
my daughter has a 1995 chevy blazer .with a 4.3 with the spider injection system
i had a check engine light coming on .and had a really bad mis fire at an idle it gets so bad it wants to die at red lights.

I had it tested and always shows different codes except code 300
so far i have replaced ,iac motor - plugs,wires,cap,rotor , map sensor, downstream 02 sensor , cat converter , it has a new egr and i rechecked it to see if there are any clogs or any carbon it is clean . Also it smells kinda bad when its idling , and always cleared the codes after replacing the parts

getting pretty expensive now and i'm getting pretty annoyed any ideas

[ricksza]

Originally Posted by brizzo123

Hey
my daughter has a 1995 chevy blazer .with a 4.3 with the spider injection system
i had a check engine light coming on .and had a really bad mis fire at an idle it gets so bad it wants to die at red lights.

I had it tested and always shows different codes except code 300
so far i have replaced ,iac motor - plugs,wires,cap,rotor , map sensor, downstream 02 sensor , cat converter , it has a new egr and i rechecked it to see if there are any clogs or any carbon it is clean . Also it smells kinda bad when its idling , and always cleared the codes after replacing the parts

getting pretty expensive now and i'm getting pretty annoyed any ideas

Do you mean that there is always P0300 plus other codes? Have you checked the fuel pressure? Does it hold steady after shutting off or drop?

You need to understand that a misfire can affect other sensors even if they are good. Example: Engine misfire = rough idle = low engine vacuum = MAP sensor code even though the sensor is good.

[old_master]

Do the spark plug wires plug into the cap vertically or horizontally? What brand of spark plugs, spark plug wires, distributor cap and rotor did you use? 4.3's are very fussy when it comes to ignition parts, aftermarket stuff just doesn't cut it.

[trcknup]

Pull the dipstick and smell the oil. If it smells like GAS it is probably the fuel injector pressure regulator or return lines leaking inside the plenum. Also check the oil level if it's higher than normal it's most definately getting gas in the oil from the above problem.