1994 Mercury Topaz



September, 17, 2008 AT 1:08 PM

Engine Performance problem
1994 Mercury Topaz 4 cyl Front Wheel Drive Manual

My 94 Topaz just started to idle fast within the last month. I have checked the MAF, TPS, air bypass valve and can't seem to figure out the problem. The engine is a 2.3l multiport fi 4cly. I have checked the vacume lines. Do you have any solutions for this or what I should do next. I replaced the MAF

2 Answers



September, 17, 2008 AT 1:10 PM

Too fast an idle speed. If an engine without computerized idle speed control is idling too fast and refuses to come down to a normal idle speed despite your best efforts to back off the carburetor idle speed screw or air bypass adjustment screw (fuel injection), air is getting past the throttle somewhere. Common leak paths include the carburetor and throttle body gaskets, carburetor insulator spacers, intake manifold gaskets, and of course, any of the engine's vacuum fittings, hoses and accessories. It is even possible that leaky O-rings around the fuel injectors are allowing air to leak past the seals. Another overlooked item can be a worn throttle shaft and a defective idle speed speed control motor/valve stuck in the extended (high idle speed) position/throttle position sensor. Also the throttle plate could be binding in its bore and kinked accelerator cable, coolant temperature sensor might not be operating properly misleading the computer that the engine is still cold and computer throwing fuel at it raising the idle speed.


Agnes Phillips

November, 18, 2010 AT 7:21 PM

1994 Mercury Topaz 3.0 eng Check eng light stays on, how to fix

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