Cannot scan ecu-check engine light will not work

SOURCE: 1996 Nissan Sentra Idles Roughly, Cuts Off, Engine Light Stays On

if this is an automatic there will be a dip stick if it is a manual you do not use transmission fluid to find out what sencor is bad take car to advance auto parts they have a digatal reader and can tell wou what sencer went bad and where it is located

SOURCE: 2002 Toyota Tundra Stalls

The throttle body needs cleaning. It has some carbon build up, and when the battery went dead the computer lost its learned values, one of which is base throttle position. Now its reset back to factory specs, not accounting for a dirty throttle body. Seen it a million times

SOURCE: 2003 Silverado rough idle, idles good after "check engine" light

Check your o2 sensor voltage, those trucks are real bad for o2 sensors, and yes if one sensor is reading 0mv, the others will start to drop out, and the vehicle will run very, rough. You also may check fuel system pressure, should be almost 60p.s.i. If its alot lower, Id be looking into a fuel pump. If that vehicle is drive-by-wire (no throttle cable), the throttle bodies get very dirty and cause that concern also. Id start by having the vehicle scantested.

Jerry Koski

• 443 Answers
• Posted on Apr 12, 2009

SOURCE: rough idle, backfire on acceleration

check everything you can under the hood your air intake system all of it especially make sure all clamps are tight .. and make sure all vacuum hoses are good and not cracking or broken or just loose . you might run a little fuel cleaner through a tank of gas too cleaning the engine fuel system up some. just a few ideas.. Jerry

SOURCE: COLD START ROUGH IDLE

I hate to be the barer of bad news, but may be the head gasket.

My car started with rough idle. Then very hard to start in cold weather. Next started overheating, but no output from heater. Trickling sound from behind dash board. Overflow bottle overflowing.......

I replaced the water pump, radiator cap, thermostat, coolant, fan belts, power flushed the system. Nothing worked. Some research gave me the answer.

The head gasket leak was allowing exhaust gases to enter the cooling system, displacing the coolant. After use, as engine cools, coolant is sucked back into the system and coolant seeps into the cylinder. This gets worse over time.

First thing you'll notice is the rough idle as the spark plug burns off the coolant in the cylinder. (This is especially true at low temperatures.) If it is the head gasket, the other symptoms will follow as time goes by.