I went and saw a car listed on FB Market Place. It is an 84 and other than the paint it looks pretty good. I got the Carfax and there is an odd error. So, in 2016 there is an odometer reading of 22,000 then in 2017 it is 22,400. There is a record again in 2020 that says it has 107,000 miles on it.
There are no other records after that.

Seller claims it has 32,000 original miles on it.

Is it easy to roll these things back.... or can that massive jump in two years be chopped up to an error in the report? Based on the car fax it appears there have only been three owners.

How concerned should I be.

 

What is the likelihood that a 42 year old car only has 32,000 miles? What does the seller have to reinforce his claim of "32,000 miles". When did he purchase the car? If it was after 2020 when it was reported as 107,000 be very, very skeptical. YES! These odometers are EASY to "adjust" to any mileage you want them to be. EASY! Also, consider that it is on Marketplace. Would a true low mileage car with condition commensurate with that low mileage really be on Marketplace? If the low mileage can be substantiated, BaT would accept it for listing. Ask the seller if he tried to list on BaT.

If it has 107k, and you really want an 84, that should not necessarily be a deal-breaker. If the car meets your expectations for condition and content, the mileage isn't that important. BUT. Don't over pay based on it being "low mileage". You and the seller may be too far apart to make a deal if he thinks it is worth 3X what a 107k mile 84 (or the same as an equivalent condition 85) is. Do your research, learn what 84s sell for in comparison to later years, even the 85, which is more desirable in the market place than an 84. Take into consideration automatic vs 4+3 manual, although it is still an 84 so manual transmissions don't command the price premium over automatic like they do in later years.

Whatever you do, don't purchase an 84 off Marketplace without conducting a personal, close, visual inspection and test drive. If you're purchasing sight-unseen, offer half of what your research tells you the price should be. Explain to the seller that you're taking a lot of risk that the car isn't what he says it is, (it's on Marketplace after all) and you have transportation costs too.

Don't over-pay (compared to later years) for an 84.

 

Does the seller have maintenance records, with corresponding mileage noted at each maintenance action or repair? How long have they owned it? Does mileage progression seem consistent with the exception of the 100k entry? What company or organization made the 100k entry?

I have seen erroneous mileage entries on Carfax, as well as fraudulent entries. I think determination of which it is depends on supporing mileage documentation. As mentioned in the previous reply, these odometers are very easy to roll back or swap.

I bought an 87 Corvette in August with 37,700 miles, and I'm confident the mileage is correct because the owner had it for 34 years, had maintenance receipts, and carfax mileage entries were consistent. Many other C4s that were being dumped after a year or two of ownership had little or no maintenance history, and inconsistent carfax mileage updates. I went with the car that had documentation.

Maintenance records make all the difference and a car with them is worth more, a car without is worth less. How much more or less is at the discretion of the buyer. A major advantage of being a buyer in the C4 market is there are lots of good ones. Wait for one with supporting paperwork and an owner who's had and cared for it for a while if you're paying market value.

 

It’s not hard to roll these back.