P0303/P0302 2007 Toyota with 56k miles - now absent P0117 (need engine replacement)

Question

I have a 2007 Toyota Camry (with 56400 miles on it). About 4 weeks back, I got the "check engine light on" and took it to neary toyota dealer. Dealer summary: Performed system test and diagnosis found codes P0302 P0303 stored random misfire, further inspected found spark plugs fouled and injection system contaminated. Replaced spark plugs with air/fuel injection services and fuel additive. cleard codes and road test operating asdesigned. advised client may have had contamination in fuel. THe service cost me $400.
After few days, I again got the check engine light and this time the dealer told me that fuel level was low in the car and old "bad" fuel might still be there. After refuelling, I still had the check engine light and took it back to the dealer. He said that now he see error codes P0302,P0303 and P0117. He said the engine needs to be rebuilt since coolant is leaking into the engine. To replace the engine with a 100,000 mile engine will cost me $5000. I took it to a independent mechanic who asked me if the engine runs hot. I did note that at higher speed the temps go up. I drive it at 40mph and engine temp seems to stay steady. He said the coolant was leaking. I did not drive the car for 10 days and took it to a goodrich repair shop for a second opinion. He said error codes P0302 and P0303 and $400 again to fix the spark plugs and car should be fine. Please advise.

Answer 1

P0303 Misfire number 3 cylinder

P0302 Misfire number 2 cylinder

P0117 Engine coolant temperature sensor circuit low input

If there is coolant entering the combustion chamber for the number 3 or 2 cylinder you would need a headgasket, Bad fuel usually set a Random mifire condition with a lean condition such as a P0171, Check the sparkplug for cylinder number 2 or 3 if it has coolant on it, you would need a headgasket. 56,000 miles is a young engine.