• Commas don't look very good after numbering. Save commas for uses like "dumb, stupid, poor autotrader scammer".
• Is my engine in perfect condition?  Well, yes as a matter of fact, it's so perfect, I eat off it every night.  In fact, the 80,000 miles I have listed in the ad were just a joke.  I've never even driven the car.
• Now,, about that period after the question mark..  I too like putting double punctuation marks,, but in a question,, you should definitely use two questions marks to get your point across..
• Suggested fix: "1.. Is the engine in good enough condition that I can use it to cook cow tongue????" (notice I used four "?"s for even better emphasis)

• Now, this is just too much of a loaded question for someone to answer easily. I suggest just reading the ad first to see if it gives you any clues on miles of the car.  

"4, are you the owner before placing it for sale?. "

• I forgive you of making this mistake, after all your country is a little backwards.  Here in the US, it is illegal to sell something that doesn't belong to you...I know, I know, it may seem weird, but we have these things called "laws" that protect personal property rights.

"5, If yes, for how long did you use car?."

• Me use car long time. 

• Now I use the "3,1,1,3,2" pattern for beginning sentence capitalization as much as the next guy, but try mixing it up a little bit to be more attractive to the eye.  I suggest starting the first five sentences with lower case letters, then capitalizing the last five.
• Did you use google translator?  I think it must have gotten confused between your "click", "clack", "pop", and "meeeewwww".  The proper tense is "involvered".

"7, what about mechanical defectives on the car? "

• Once again, I think you used the wrong word.  I believe you meant "detectives".
• In answer to the question, yes,  I keep a couple mechanical detectives on the hood most of the time, just in case something goes wrong.

• This is one of the easiest mistakes to make.  You accidentally leave out a space, and spell check doesn't pick up the mistake since it creates an actual word that's spelled correctly.  I believe you meant "in tension".
• Yes, the tension of selling the car is killing me. 

• This question is a little too personal.  I don't feel comfortable talking about my sexual partners over email. 

• Did I send you pics?  It must be some new feature of AutoTrader to send pictures to people who are thinking about buying a car.  In fact, I only posted one picture, so I'm curious as to what was in those other pictures you were sent.
• "Finally"... Yeah tell me about it.  It took you way too long to figure out that this car was what you wanted.  Some a$$holes would have even waited until they got an answer to their questions in the email before they could make up their mind.  I'm glad it only took you this long.

• "NB" I'm having trouble figuring out what this stands for.  Nude Beach?  Nice Butt?  N...B... ????
• I'll get back as soon as possible so you can get posted.  I love getting posted.