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rpmdiag, Tech and Instructor
Category: Ford
Satisfied Customers: 6716
Experience:  Since 1975
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I have recently purchased a 91 f150 5.0, it has 62500

Customer Question

I have recently purchased a 91 f150 5.0, it has 62500 original miles on it. It sat for 2 years due to the death of the original owner. When purchased it ran great, no missing, sputtering etc. after about 150 miles when it gets warm/hot it has no power and the gas has to be feathered or it stalls. It idles fine but also when hot if revved it acts like there is a lot of back pressure. ran key on engine off diagnostic and gives memory code for o2 sensor lean. I was planning on going through fuel system, filter replacement, injector cleaning this weekend until this started. key on engine running gave 111 all normal code.
Submitted: 4 months ago.
Category: Ford
Expert:  rpmdiag replied 4 months ago.

Hi, I’m Ron and I can help you.
I have been in the auto repair business with my own shops since 1975 and also teach automotive repair. I am confident we can resolve your problem together. Please understand that I don't know your skill level. In most cases when you have a problem with the way the vehicle performs, specialized tooling is required to acquire computer data/information or engine testing results. We didn’t build these complicated vehicles; we just diagnose and fix them. Also understand that I can't see, smell, hear, or touch the vehicle either, so it may take a few replies to get to satisfactory results. I am also going to direct you with the fastest, easiest and most common things to check first. Please be patient and permit me to do what I do best.
I also try to give all of the information you may need, expecting a “positive rating” in return. I will also continue assisting you after you have rated me, if necessary. If there is any reason I cannot get a positive rating, please let me know why “in advance”, so I can go another direction for you. I am sorry you’re having this problem; I’ll help you through it.

Check the fuel pressure with a gauge, and check to see if that gas is still good.

Thanks, Ron