been havin trouble with my blazer running rough lately. already checked the egr, maf, iac, and spider. at 135k im sure she needs plugs, wires, dist. cap, rotor,etc., but i also have a leaky muffler. how much of my trouble could be
due to the muffler im wondering? patience is truely a virtue. 95jblaze

 

Well... your gonna have to fix the muffler anyways... so fix it first and see what happens. I would also do the tune up that you are eluding to. Do you have a check engine light?

 

I moved your thread to the '2nd Gen Tech' section, assuming that you're driving a '95 Blazer.
As to whether the 'leaking' muffler could be causing your problems, I'd say 'no'.

 

Is the muffler leaking or is there a leak in the exhaust closer to the engine? If you have an exhaust leak before the O2 sensor, it definitely can affect engine performance.

 

thanks for your response bandidolenny. my tentative plan of action was to start with the muffler then proceed to the tune up as you said. as for my ses, the only codes i have gotten are for the camshaft position sensor, and an 02 sensor that hasnt returned since being cleared awhile back. 95jblaze

you assume correctly rriddle3. sorry for posting in the wrong place, hope it didnt cause you too much grief, im a 'newb'. as for the muffler, i fear that you may be right, im just trying a little process of elimination by picking the brains of guys like you. thanks for your response. 95jblaze

thanks for you response swartlkk. i didnt find any other leaks apart from the muffler, but i will take another look upon you suggestion. as i told bandidolenny, i have had a code for an o2 sensor before, but it wasnt showing after being cleared. if it were bad, wouldnt it have immediately thrown a code? 95jblaze

 

The problem with O2 sensors is that as they age, they get lazy and have a delayed response. That delay can vary depending on operating conditions of the vehicle. What was the specific code?

 

p1133(o2 sensor, insufficient switching) was the specific code. i also got a p1442 code that i had forgotten about until your request for the o2 code. i couldnt find it in my haynes manual, but i think i was told that it was a dealer specific code, whatever that means. 95jblaze