Hey, my truck has been running a lot rougher lately then it had since i bought it. the idle is very rough and the rpm needle jumps up and down a little bit. I was told by the dealership that it was the manifold gasket, so i paid about 700 bucks to get that replaced. it ran slightly better for a while, but now it runs as rough if not rougher then before. from what i have read, this may be an issue with the 02 sensor, is there any way to check it without bringing it into a dealership? i read somewhere that you have to heat the end with a blowtorch or something, is there any other way? thanks guys, any ideas or thoughts are more then appreciated!

 

what year truck?....waht type engine?.........you can use a scan tool to see if the o2 sensors work......upstream o2's will vary in voltage and down strewam o2's will remain @ a constant voltage.......looks like on the first problem you got was an idle air control(IAC) problem........if it runs rough now....you may want to check the vacuum your engine pulls.......like i said use a scan tool......