Engine Performance problem
2000 Dodge Caravan 4 cyl Two Wheel Drive Automatic 125000 miles
Just two days ago with no warning, our 2000 Dodge Caravan Sport (base model - no extras) started running sluggish when I depressed the accelerator. I let of a little and it would go, but not if I punched it again. Being hot or cold didn't seem to matter, either. Last time I had the van repaired our mechanic told us we should replace the spark plug wires. I reasoned that changing the spark plugs and wires couldn't make things worse so I gave it a shot. When I finished, the van would turn over, but it would not start. Hanes is helpful, but it bounces from chapter to chapter and is hard to follow if you lack confidence in fixing your own vehicle. I did not use the busing rings that come with te plugs because there were no instructions to do so on the box the spark plugs came in, nor in the Hanes manual. I thought this might have damaged something since I tried to start it for 10 minutes before giving up. I later put the rings on, but the symptoms did not change.
I moved on to the more challenging problems based on the Hanes manual troubleshooting guide under " Engine turns over but won't stay on" and the next thing I started to replace is the fuel pump and filter. However, now when I turn the ignition to on without engaging the starter loud clicking noise comes from the relay box. When I tried to find out which one it was I narrowed it down to three relays including " A/C Clutch Relay", " Auto Shutdown Relay", and " Fuel Pump Relay". The clicking was so severe I couldn't tell if one or all of these were going haywire. Since all of the relays are the same I tried unsuccessfully to fix the problem by swapping some of the relays.
Now, my van is on jack stands waiting for me to take down the fuel tank (after I empty it) and replace the filter and pump.
Once the fuel pump is running on a Chrysler product, it is extremely rare for them to cause a problem while driving. By just throwing more and more parts at it, you're adding more variables and potential problems. This will make it very hard to diagnose the original problem.
It is almost unheard of to fix a running problem on a Chrysler product by replacing the fuel filter. It is more likely you'll find a plugged pickup screen in the tank, but the symptom will be the engine dies when the largest volume of fuel is being pumped, which is during coasting at highway speeds. Less fuel is moved during acceleration so it's easier to maintain the necessary pressure.
The " rings" for the spark plugs are gaskets. Although unlikely, pull a spark plug back out and check the gap. Without the gasket in place, the plug could have been screwed in too far, and the piston might have hit the electrode closing the gap. Since the no-start problem first occurred after replacing the plugs, wouldn't it make sense to put the old plugs back in? At the very least, physically compare a new plug to an old one.
As for sluggish running, my first guess would be a MAP sensor, particularly since throttle position had an effect on the symptom. Now that it doesn't start at all, I would suspect a defective camshaft position sensor or crankshaft position sensor. Normally, either of these sensors will set a diagnostic fault code and turn on the " Check Engine" light. Retrieving the fault code will tell you which sensor is causing the problem. It is possible for the MAP sensor to report incorrect values that result in poor performance, but as long as the incorrect values fall within the acceptable range, a fault code will not be set in memory. Eventually, the sensor will fail completely; then a fault code will be set, and the Check Engine light will turn on.