The engine is only running on 3 cylinders there seems to be no spark on one of the cylinders and when I pulled out the spark plug it was dirty. Could it be that there's no flow on one of the injector? I will do a compression check and a fuel pressure check to see what's going on. But I was just wondering if anyone has experienced this problem. Thanks.

 

To check your ignition, you can either purchase a spark tester or:

Performing this test at night or in a dark area will make it easier to see the sparks. Warm the car up completely to normal operating temperature or as hot as your motor gets. Ignition components are affected by heat and problems with those parts may not show up until the engine is hot. Disable the fuel injectors and get a new or known good spark plug. Set the gap of this plug to your vehicle's specifications and make sure it is clean afterward. Wear gloves (welding gloves work great), preferably with latex or nitrile gloves underneath, and remove a spark plug wire from its plug. Connect the good plug to the end of the wire. Hold the plastic deep-well tube by the rubber boot at the tip of the wire end with the threads of the plug touching clean, bare metal on the valve cover. Have an assistant crank the motor while you watch the spark, carefully keeping all body parts as far from the plug, motor and metal body parts as possible. You're not just avoiding touching the source of the voltage, but also any grounded metal. Different types of plugs have different colored sparks but usually a good spark is a thick, strong flow of bright pink or is at least bright. Little "lightning bolts" indicate a weak ignition. Check all four wires. If the sparks at all of the wires are weak, try holding the threads of the plug against the battery negative post to see if the better ground makes a stronger spark. This will test your entire ignition.

You follow a similar procedure when using a spark tester. If only one cylinder is not getting spark, the cause will either be the distributor cap, plug wire or the plug itself. Switch the wire of the bad cylinder with another while you are testing and see if the lack of spark moves with the wire. If it does, you need to replace at least that one plug wire. A fresh new set would be better.