P300 code after replacing head gasket

My truck is throwing a P300 code after replacing rod valve and head gasket at shop as Wel as fuel injectors. I changed the throttle body to after market and it ran good for a few miles. My dad insists it’s the ECU going bad and I think the more expensive throttle body will fix it

 

If the ECU worked before the swap its unlikely its bad now. P0300 is random misfire and can be a boat load of stuff. You need to start by watching a misfire counter and rechecking all the work.

Lastly on Tacomaworld we reserve "help" titles for emergencies with off-roading/break downs, if you could rename the title to P0300 after swap etc, it would be best.

 

What is a rod valve?

Why did you change to the aftermarket throttle body? Do you still have the stock throttle body? If so put it back on.

What does the shop that did all this work say about things?

 

No such thing as a rod valve
Except on a step side model with the optional muffler bearing set up. Jk.
Lots of missing info needed. Year, engine, mothers maiden name.
On the helpful side the ecu is most likely the last on the list of items unless there is alot more pointing to it.

I'd look over the engine for anything related to causing a light misfire that could have been related to the headgasjet replacement. Like improperly plumbed, loose or disconnected vacuum hose. loose spark plugs, etc. everything touched.​

 

Please change the title of the thread. There is a button at the top on threads you create

 

Did you look at the after market throttle body after install and make sure its operating correctly?

 

Which cylinder(s) are misfiring?

Was it doing this prior to the work?
Why were the injectors replaced? Where did they come from? (If Amazon/ebay toss them in the trash and either put the old ones in or get some good ones from a parts store, dealer, or rock auto).
Why was the throttle body replaced?

Never seen a faulty throttle body cause a misfire.