Was it a new/unrun engine or used? Usually worn out engines will quit when they get warm due to loss of piston seal and thus compression gets low when warm. If it was new, then most likely you’re running it too lean.

What fuel (brand, nitro %, and oil %), and glow plug are you using? Have you checked the truck over for worn/loose bearings? Binding in the driveline? Fuel system is leak free?

With 30% nitro, you need to make sure your glow plug isn’t too hot. That’s usually problem #1. Use a medium heat plug - if it has the standard plug head, McCoy MC8 or Novarossi C6S are great plugs. Picco P6S are the best standard plugs I’ve ever used, but they’re hard to find. If your engine has a Turbo plug head, use a P6TH.

Piccos like to run fat!!!!!!. If you try to run them on the ragged edge of too lean, they will be unhappy. I have a modified P3 .28, so I know firsthand. Riches the low speed a half turn and open the high speed one full turn from where they’re at now. This should be quite rich. If the top end doesn’t blubber a little bit when you run WOT, open the needle richer until it does so you have a point of reference. When it’s blubbering, it’s 4-stroking. Tune it leaner 1/16th turn at a time doing a WOT pass between each adjustment and listen to the engine. Lean it down until the blubbering stops, then lean the top 1/16th turn more. Lean the low speed so it transitions to WOT cleanly after up to a 20sec idle. What you want it to do is be slightly loaded up after 15-20 seconds of idling and still clean out and throttle up. If there is no loading after 20 seconds (launches clean and perfect), it’s too lean.

Make sure your head shim stack totals .4mm or more (.015” minimum!). Also make sure your fuel has 10-11% oil. Less in this case is NOT more - especially if full synthetic. They like a castor blend. And last but not least, the idle gap needs to be .5mm-.75mm. No more! If the idle gap is wide, your tuning will be fruitless!!

The high speed needle is in the housing that the fuel line is connected to from the tank. The low speed needle is in the end of the throttle slide. The base setting is having the head of the screw (needle) flush with its housing. The low speed should be proud of the throttle arm linkage by a little bit. From flush, it probably needs to come out 1/2-1 full turn richer. This is a VERY loose base setting. Likely it will be rich if everything is done correctly.

Proud is an old school term that basically means “to stick out a little bit” or to be “above the surface of”. The low speed needle will stick out from the end of the throttle arm roughly the depth of the low speed needle’s screwdriver groove give or take a little tiny bit.