I have a 2003 blazer manual transmission. I am having problems with my gauges and my engine jerking. I noticed last week my temperature gauge would go to zero back to 190ish. Everytime it did this my engine would jump. I replaced the temperature sensor but that did not fix the problem. Now it wont start evertime, I have power and gas. Another problem is when I do get it started while it is idling the rpm gauge, temp gauge, and oil gauge will start fluctuating. It will do it sometimes at high speeds but mostly only at low speeds and while idling, any thoughts? The fuel filter was replaced a few weeks ago spark plugs last year.

 

For such a mass gauge error, I would put the blame on a bad ground wire. I just don't know exactly, because there can be multiple power and ground wire paths and connections. A good place to start would be looking for corroded or broken wires. A wiring diagram and ground & splice locator would be a good place to start in giving some key locations that would be a place to start. Everything has to have an individual power wire, but alot of vehicle items tend to share a common ground wire and for more then one to be failing, it sounds like a ground wire.

Also, it could be the PCM or engine computer. The computer usually provides power as well as ground for alot electronic functions controlling engine tune. You mentioned that the engine acts up when the temp gauge goes from 190 to 0 and back; which is changing the engine tune from hot to cold.

 

Good deal, I'll look into that, appreaciate it. Now I noticed the car has trouble starting after it has warmed up (it starts up everytime when the engine is cold). For instance, if I drive it for a half hour turn it off and then try to turn it back on it acts like its out of gas. I can hear the fuel pump, and yesterday I could actually smell gas. Could bad wiring cause that as well, thanks.

 

The smell of gas means you got a fuel leak somewhere. Try driving around for while and after you stop, start looking around the fuel tank and lines for wet spots. Also, I've heard that the evaporative emissions system and can have a fuel smell to it if it has failed; usually a SES light will pop up if it has.