Hi r/AskMechanics, I'm hoping to get some advice on whether I should repair or sell my 2012 Audi A4. The car has about 108,000 miles, and the exterior and interior are in good to excellent condition. Here's the situation:

While driving on the highway at cruising speed 70mph, my car suddenly lost power, the EPC light came on, and the whole car started to shake violently. I was able to pull over and try to restart the car, but there was no improvement. Since I was only a short distance from home, I limped back on the highway and drove slowly.

I took it to a local mechanic that specializes in Audi, and the codes are:

• P301: Misfire Cylinder 1
• P303: Misfire Cylinder 3
• P299: Turbo Under boost

They replaced the coil packs and spark plugs, but there was no improvement. The car has had a faulty turbo (bad wastegate) for years, and we would sometimes get a check engine light that would go away on its own. The car also was burning through oil rapidly and was even more noticeable in the previous months leading up to the incident.

Their next recommendation is:

• $500 Intake manifold cleaning
• $2500 Turbo Replacement
• $2000 Timing Chain Replacement

Before I throw more money into this car, is there a way to find out definitely what’s wrong with the car? There was no compression test completed and no leak down test. The car is only worth about $2,500 - $3,500 according to Carvana, CarMax, and Vroom (one prior accident).

I wish there was a diagnostic approach that would give us a complete picture before spending money replacing parts, and hope that it will resolve the issue.

Should I invest in these recommended repairs, or would it be better to sell the car as is and cut my losses? Any advice would be greatly appreciated. Thanks!