| The Problem | Is Caused By | What To Do |
|---|---|---|
| Hard starting (Engine cranks normally) | Faulty engine control system component | Repair or replace as necessary |
| Faulty fuel pump | Replace fuel pump | |
| Faulty fuel system component | Repair or replace as necessary | |
| Faulty ignition coil | Test and replace as necessary | |
| Improper spark plug gap | Adjust gap | |
| Incorrect ignition timing | Adjust timing | |
| Incorrect valve timing | Check valve timing; repair as necessary | |
| Rough idle or stalling | Incorrect curb or fast idle spec | Adjust curb or fast idle speed (if possible) |
| Incorrect ignition timing | Adjust timing to specification | |
| Faulty EGR valve operation | Test EGR system and replace as necessary | |
| Faulty PCV valve air flow | Test PCV valve and replace as necessary | |
| Faulty TAC vacuum motor or valve | Repair as necessary | |
| Air leak into manifold vacuum | Inspect manifold vacuum connections and repair as necessary | |
| Faulty distributor rotor or cap | Replace rotor or cap (Distributor systems only) | |
| Improperly seated valves | Test cylinder compression, repair as necessary | |
| Incorrect ignition wiring | Inspect wiring and correct as necessary | |
| Faulty ignition coil | Test coil and replace as necessary | |
| Restricted air vent or idle passages | Clean passages | |
| Restricted air cleaner | Clean or replace air cleaner filter element | |
| Faulty low speed operation | Restricted idle air vents and passages | Clean air vents and passages |
| Restricted air cleaner | Clean or replace air cleaner filter element | |
| Faulty spark plugs | Clean or replace spark plugs | |
| Dirty, corroded, or loose igniter secondary circuit wire connections | Clean or tighten secondary circuit wire connections | |
| Faulty ignition coil high voltage wire | Replace ignition coil high voltage wire (Distributor systems only) | |
| Faulty distributor cap | Replace cap (Distributor systems only) | |
| Faulty acceleration | Incorrect ignition timing | Adjust timing |
| Faulty fuel system component | Repair or replace as necessary | |
| Faulty spark plug(s) | Clean or replace spark plug(s) | |
| Improperly seated valves | Test cylinder compression, repair as necessary | |
| Faulty ignition coil | Test coil and replace as necessary | |