QuestionI've never had a problem starting my car while the engine is cold but after the car is warm sometimes it takes at least fifteen minutes, or until the vehicle cools off, before it will start again. It "chugs" sometimes while driving. Several times I've noticed inconsistent idling - the RPM's sometimes run up to 4000. I have replaced the crank sensor and fuel pressure regulator with no change.
AnswerHi, Bobby.
For your problem with the vehicle not starting, you'll want to check for the following when the problem is occurring:
1. Does the check engine lamp illuminate? If it doesn't, it's a safe bet that the engine control module hasn't powered up properly.
2. Do you have spark? You can test for this by pulling the number 2 wire-- the longest accessible wire-- off the spark plug and placing a spare plug in it and then laying the plug on the intake manifold and cranking the engine. If you do not have spark, you should probably investigate the installation of the crank sensor.
3. Do you have fuel pressure? You won't readily be able to test this properly unless you have a fuel pressure gauge installed, but you can make a rudimentary test by loosening the nuts on the fuel line where it attaches to the fuel rail. Once you've pulled the line out of the rail enough so that the o-ring is completely out of the rail, fuel should squirt out. If it doesn't, you have no fuel pressure. Keep in mind to do this after you've done the spark test and after you've reinstalled the plug wire. Otherwise, you could start a fire with the combination of spark and spilled fuel.
For the "chugging," it sounds like your engine may be misfiring. The most common causes of misfires are defective secondary ignition components (spark plugs, plug wires, ignition coil), so I'd recommend checking these items first.
In reference to the inconsistent idle, you may have a problem with a throttle cable or the throttle position sensor. Check the cables to verify there is some slack.
For all the items, I'd suggest reading the diagnostic trouble codes. Some of the symptoms you list rarely appear without the check engine lamp illuminating, so the potential is great that you will have stored diagnostic trouble codes that will lead you more directly to the problem. Most national parts store chains will read diagnostic trouble codes for no charge. If you have this done, do report the codes in a follow-up, and I'll do my best to advise you on what they mean and how to diagnose further.
