Well i have been fighting a problem for the last 4 years now. Today , i can say it has been fixed. During the hottest months , July, Aug, Sept. , if i drove the jeep and got up to normal operating temps cut it off while i go into a bank , then come out and get in it and crank it up, the heat under the hood was vaporizing the fuel in the number 3 fuel injector. It would run rough , maybe even go dead. I have applied the TSB's but to no avail. I cut the holes in the hood and put on a poison spider louvered hood vent on it today. It looks good and lets out the heat. Drove it today and no problems at all. The engine is running about 10 to 15 degrees cooler also. Problem solved. I was ready to sell the jeep, but no way now. I went from 13 to 16 miles a gallon, but besides this problem , i also had a cracked 0331 head. This was also repaired. Maybe a combination of fixing these problem helped gain the mpg