New, here on the forum. I have been living here in Costa Rica for 11 years now. Most mechanics do not know how to work on american cars, only Asian imports. With that being said,I have a 2000 Blazer LE with the 4.3 ltr. vortex engine. Here's the problem. If I visit the U.S. and let my car sit for a couple of weeks, when I come back and start the car, it runs fine for a day or 2. Then, this problem occurs. It starts to misfire, like one cylinder is missing. It bumps hard when idling. Also, the temp gauge goes crazy. Up and down to eventually all the way down. I replaced both o2 sensors and had the injectors cleans. I replaced the mass air flow sensor and then my mechanic sid the new one was bad so he put the old one back on. Still having problems. Any help would be greatly appreciated.

 

Does the temp gauge go crazy at the same time the engine starts to miss? Does the temp gauge behave itself all the time that the engine runs well? Is the SES light on? If so, what are the stored codes? If engine is missing there should be a misfire code stored at a minimum of "pending"

 

sounds like temp sensor to me

 

The temp gauge goes crazy when it starts to misfire. Now if appears that not working at all. I will put it back on the computer and get a code next week.

 

The temp sensor can make it misfire? Didn't know that, however, I'm not a mechanic. I really do appreciate the help.

 

Would that be the intake temp. sensor, coolant temp sensor, air charge temp sensor or the ambient air temp sensor? Kinda confused here.

 

Coolant temp next to 3 plug. Had mine come unplugged and ran like crap and gauges all over the place

 

Also look at the coolant temp the PCM is seeing while you are at it.