Rep Power: 0

So the other day i was on the freeway driving as normal going about 70mph, out of nowhere there’s one clunk/bang/pop kind of sound, my battery light starts flashing, and my check engine light comes on.

All of this happend at one time then immediately after my car dramatically loses power and im stuck going 50mph cant go any faster, and my car wont go above 1000rpms, and the temperature gage dropped all the way to cold.

I get it towed to the shop, its been there for almost 2 days now and they dont know whats wrong with it.
They say it starts up and then the rpms surge while its in park, the battery light is on (they already put a new one at this point) then 2 minutes later it stops surging, the battery light turns off, engine light turns back on, and it sounds as if its running just fine, however it still isnt able to get over 1000rpms.

They hooked it up to the computer and said its not reading any codes at all, and they need to call mike the rocket scientist to come diagnose it. I trust mike but they said it could be like 3 days before he could even show up so i figured i would look for someone who maybe knew something more on here.

If you have any idea of whats wrong with it please let me know i will GREATLY appreciate it. The only guess the mechanic had was that my old battery shorted out and shorted something in the computer of the car.

Please let me know, and thank you for any help

 
Rep Power: 222

Check timing and check alternator would be my first checks

 
Rep Power: 229

-Battery light points to alternator/alt belt/tensioner

-no ecu communication points to electrical issues, I'd check that all your grounds are connected and tight, then check the fuses and relays

-rpm locked low could be many things, the ecu will need a scan when you get it working to find out

was there any sign of a collision with road debris, or electrical fire, or other odd looking issues?

 
Rep Power: 0

i had timing belt replaced around a year ago to prevent it from breaking and messing stuff up, and the mechanic said the alternator was fine. I had them drive it to another shop close by and see if maybe their computer will run a code on it, or if they know something more about it. Havent heard anything from the new shop yet. Thank you for the advice though i will definitely have the new shop give it a double check for the alternator and timing.

 
Rep Power: 0

No sign of collision, fire or anything else.
I do have an after market sound system though (2 amps, and a 10.5 inch sub) and i asked the mechanic if maybe that couldve caused the battery to short something out in the computer. He said thats always a possibility, but ive had the soundsystem 2+ years with 0 problems, and i feel like if it shorted the battery out it would probably short itself out too and be broken but its still fine.

I’ve honestly had so many problems with this car i feel like it could be anything, but a computer issue seems the most logical to me, otherwise i dont know why it wouldnt read any codes unless the light sensor is just broken (which is obviously not the case bc the car gets no power to the ground).

Thank you for the advice and i will definitely tell the shop to make sure everything is grounded and tightened, and to check the fuses and relays. Thanks again

 
Rep Power: 367

check for alternator loose bolts
it's common issue

 
Rep Power: 224

Very common, and causes basically everything you mentioned.

 
Rep Power: 134

And what is the code that is stored with the CEL on? Sounds like you are in Limp Mode to protect the engine until you diagnose and fix the problem.