by natureboy » Fri Feb 04, 2011 10:56 pm
My Hayne's manual lists 10 possibilities:
1. idle speed too high
2. ignition timing incorrect (too far advanced)
3. incorrect spark plug heat range
4. intake air leak
5. carbon build up in combustion chambers
6. valves sticking
7. valve clearances incorrect
8. EGR system not operating properly
9. fuel shut off system not operating properly (fuel injection only)
10. engine overheating
If the head is badly carboned up Sea Foam won't solve it-have to pull it. Start with the easiest things first-timing, replace old vacuum hoses, loose carb or intake bolts, adjust idle, use the stock spark plugs gapped correctly, Sea Foam in 3 places-gas tank, brake booster hose and oil 15 minutes before an oil change, check for vacuum leaks with a can of carb cleaner and hose attachment.
Is this a new or old problem? How many miles? Does the engine ping under load?
87 Ram 50 long bed, 2.6l rebuilt, 5 spd, 4x4