My dad owns a 1997 Ford F150 with an automatic transmission and a 4.7L gas V6. He ran out of gas in it once and ever since then the check engine light has been on and it makes a howling sound which is loudest at 45mph. Mileage sits at 155,000 miles. What could be wrong?
sounds like failing fuel pump, but you'll never know until you scan that check engine light. That's step #1 and it's absolutely free. We can't do it telepathically.
What could be wrong?
Since the check engine light is on there are codes. What did you find when you performed a diagnostic scan?
I don't have a diagnostic scanning tool.
Most parts stores will read codes for free.
However if you're going to be working on computer-controlled vehicles you need one. An inexpensive one will do for pulling codes and most can also read live and freeze-frame data. (Reading the codes is just the beginning of the diagnostic process, data also provides valuable troubleshooting information.)
I don't have a diagnostic scanning tool. However, our mechanic looked it over and said it was fine. I personally don't believe that.
I personally don't believe that.
Nor should you. Sounds like your mechanic is spewing horse manure. Now. You go to the discount auto parts store (AutoZone, O'Reilly's, Advance Discount Auto Parts, etc) they scan the computer free of charge. they'll scan for codes and then tell us what your codes are so we can be of further assistance.
Like I said in the beginning, this truck is my dad's truck. It would be entirely up to him if he wanted additional information from a free diagnostic scan at an auto parts store. I don't think he would ever do that because this mechanic is usually a good honest mechanic. He has so much business that upselling is nowhere on his radar. Guessing from the history and from what Google said, it's probably just a bad catalytic converter.