car idles real high starting up for the time in the morning. cold weather
I have a 1994 olds cutlass 3.4 ,having idling problem when starting starts up then cuts off. I have to restart the a few time until its gets warm then its find. intake gaskets have been replace , still doing the same thing. should I replace the coil pack?
need help bad !!! Bill
IAT sensor~ https://www.google.com/#q=1994+Oldsmobile+Cutlass+Supreme+IAT+sens or
With no other running issues, it's highly unlikely (not impossible) that a coil pack is your issue. Ignition-related problems (like a coil pack, plug wires, Ignition Module, etc) tend to show up most frequently under load (during acceleration) and when the engine is hot. This is where a good diagnostic education helps...because there's a handful of things that could cause your issue. I'm going to assume the intake manifold gaskets were done properly and it's been verified that there are no vacuum leaks... There are a few possibilities...one is the Idle Air Control Valve. This may be your issue, but I hesitate to recommend their replacement because in my 10 years as an automotive tech, I've found that IAC Valves are a very common misdiagnosis for idle issues and more often than not, replacing the IAC doesn't resolve the complaint. How is the warm idle...normal? When it cuts out, does it just start and stall immediately, or does it do anything funky? How does it drive? Any Check Engine light? Details matter.
Judge....a faulty IAT will definitely cause issues, but so will a bad Coolant Temp Sensor, Mass Air Meter, etc..... The good news is that the IAT, CTS, TPS, and MAF can all be easily tested by pulling live data from a scan tool (basic cheap tools only pull codes, if you go a step-up, you'll usually be able to read live data.) The first two are just common sense...look at the data: the IAT should be close to the outside air temperature, and will get hotter as the engine heats up. The CTS is about the same, it should read fairly linear as the motor heats up to temp. The TPS can be tested by putting the key to the Run position WITHOUT starting the engine, and slowly depress the throttle from zero to 100% and back down to zero. It should be a smooth curve or a smooth numerical transition if you can't graph. The MAF has to be tested with the engine running and typically the best way to go is the "Stab Test", where you look at the MAF data or graph it and stab the throttle briefly with the engine up to temp and running. Your data should jump up and back down smoothly and fairly in unison with the data from the TPS sensor. I like to graph the two together when I'm using a high-end scan tool.
