Synptoms:
1. starts fine and revs up nicely and all seems fine. Until the rpm drops to normal
2. Then the whole engine starts shaking and sounds/feels like it is running on 4 or 5 cylinders , some times there is a loud exploding sound from the exhaust, as if I was experiencing "late" ignition (not sure about the English term here) before the engine suddenly stops.

With no luck, I have replaced both the rotor cover, all cables between the coil and the spark plugs. I have also replaced the spark plugs.

What could cause this? Bad rotor (where the spark plugs are connected)? Anything else?

 

Are there any codes stored? There are sensors at the crank and throttle plate. I suggest checking those although I (fortunately?) don't know how. You should be able to look it up in the sticky section of this area. Good luck.

 

Hi KMT,

As Jerry suggests, it would be good to check for diagnostic trouble codes stored in the Vehicle Condition Monitor (VCM). To do so:

1. Turn the key to position 2 (ON) but do not start the engine;
2. Press and release the VCM button;
3. Watch for a message to appear in the small display window below the speedometer;
4. If a code is stored, it will be in the form of FF or Fuel Fault and a two-digit number, such as FF46 or Fuel Fault 46.

If you find a code, write it down and report it here and we'll help you further.

When you replaced the rotor cover (distributor cap), did you also replace the distributor rotor? If not, I would recommend that you replace it just to rule it out.

My first impressions are that one or more of the following may be contributing to your symptoms:

1. A leak in the air intake somewhere between the Mass Air Flow sensor (MAF) and the intake manifold gasket, a vacuum leak, a leak in a crankcase breather hose, or a leaking EGR valve or EGR pipe.

2. The Idle Air Control Valve (IACV) could be clogged with carbon, preventing the conical valve from closing properly, contributing to rough idle and lean running.

3. Fuel delivery could be a problem - a clogged fuel filter or failing fuel pump, or malfunctioning fuel injectors. You could disconnect the inlet hose from the end of the fuel rail near the firewall/bulkhead, place a container below the end to catch the fuel, and crank the engine for a couple of seconds to see if the fuel supply seems sufficient. If the fuel supply seems weak, perform the same test at the inlet to the fuel filter.

4. The oxygen sensor could be lazy or stuck - you can measure the voltage at its electrical connector for proper voltage swings between just above 0 volts and just below 5 volts.

Cheers,

Don