Car runs fine 25mph and above - getting 23 to 25 mpg. When I get into stop & go traffic 20mph or below for about 15 to 20 minutes the engine starts to run on 2 cylinders and then dies. Let it sit for 20 minutes and it starts right up and runs fine until I hit traffic again. Has been doing this for about one year. No check engine light comes on. Computer check shows nothing wrong it was suggested that the idle speed sensor was the problem another mechanic said it was the spark controller in the engine. the engine is a 4cyl. 1.6L. I'm an old time ASE certified Master Auto Technician who has not worked on a car since 1995. If this was an old point and cond type I would say it had a bad coil that was heating up and breaking down but this engine has individual coils to each spark plug and I can run all day long with no problem until traffic. Any Ideas? I think your page is FANTASTIC.
Engine starts to run on 2cyl in traffic on 2002 Suzuki Vitara
You should first pull your codes from your Power Train Computer. You should have a Check Engine Light Coming on yes? Then you need to address the codes first, most likely misfire codes. You can get an OBD-II code retriever at a parts store for about $30. The fact that you can not get any codes, when there is an obvious misfire tells me that the Engine Computer is not seeing what is wrong, also it is the Engine Computer that controls the 4 individual coils that fire the plugs. So if your plugs are fresh and the correct type, you may have an engine computer failing. Try tapping on it when it is doing this malfunction and see if the engine runs any different or just dies, that is 1 way Oi check for a defective computer, GM call sit eh 'slap test' and it works pretty well. Or you could use a DVOM and then test the trigger or on/off to 1 of the coils when the car acts up, if you have no trigger, then yo know it is upstream of the i.e. the computer. This is just like testing the negative side of the coil on a points/condenser car, if the points wear and close up.
I had the same thing happen. It turned out to be the cam position sensor located in the back of the engine just below the valve cover. I hope this helps you because it drove me crazy trying to troubleshoot.
I had the same thing happen in my 2001 Vitara 1.6L. It turned out to be the cam position sensor located in the back of the engine just below the valve cover. No indication on the computer. I only found this because someone who else had the same problem told me. If you want to confirm before purchasing the part. The next time it cuts out, open the hood, remove the sensor, it's only 1 10mm bolt & elec plug, let it cool for a couple of minutes and put it back in. If the car starts that's the problem. Be prepared for a small amount of hot oil to come out when you pull the sensor.