Toyota Repair: EGR issue, coolant fluid, coolant leak

Question
Dear Ted,

                I have 95 Toyota Camry 4 Cylinders, 177000 miles. The check engine light turns on sometimes at morning times at low speeds. Then turn off over 70 mph. I did diagnostic test and get a code 71, EGR system problem. I have rough knocking engine sounds during acceleration and uphill. I changed plugs, wires and did injection system service, but the symptoms still there. I noticed that I have to check the coolant fluid more frequently or the engine will overheat since it consumes more coolant. I think I may need to change the EGR or vacuum switching valve.
What do you think?

            Thanks for your time … A. B.
                                   Houston, Texas


Answer
The engine overheating and loss of coolant needs to be addressed first, the engine noise is also cause for concern, there may be an external coolant leak or an internal leak like a leaking headgasket that causes coolant to enter the combustion chamber, which can cause the EGR system problem. I would recommend that you have a repair shop test the cooling system for a possible leak or blown headgasket.