Expert: Ben Deutschman - 7/5/2009

Question
I had the  #3 coil short out the #3 plug had a lot of carbon build up so i changed all of the plugs. now once the car is at operating temp the car will stall when i come to a stop. Honda dealership adjusted valve and the said it need a valve job.it did not do this before the coil shorted out don't see how this can cause a car to need  a valve job. the car just wont idle back down without stalling  after it is warm up any suggestions

Answer
The best way I know of to determine whether or not your car has a bad Valve, would be a Leakdown Test, and or a Compression Test. A Leakdown Test requires the use of a Compressor, and a 'Leakdown Tester', in order to measure how long each cylinder takes to lose Pressure, once pressurized by the Compressor. A Compression Test only requires a Compression Tester, and a well charged Battery in order to crank the Motor, so you can measure Compression in each cylinder. If the Compression is within a reasonable percentage of the Manufacturer's specification, and each cylinder doesn't vary wildly from the others, than usually your car's engine has good Rings and Valves. However, the Leakdown test is supposedly a more accurate test of Engine health.