4AGE 16V engine overheat when at high speed

[Rascal21]

Common for the fuel injector connectors to crack with age, you can get new with cable stumps (so you can splice the ones from engine harness onto them) on ebay for practically nothing, here's a quick example of available replacement items https://www.ebay.com/itm/Engine-Fuel-inj...SwcGhefbS7
They're the usual square Bosch type as found on most old Audi's/VW's

While you're at it, change all vacuum hoses too, get a few meters of clear silicone vacuum hoses, that way, down the line when you have other issues, you'll be able to see if your engine is suffering from vapor issues in the vacuum system, I had that happen once when I had too much oil in the engine (stupid mistake) which made it suffer from one of the most excessive blowby's I've ever seen (because my 4A-GE is an early 3-rib that has never been opened, should have had an overhaul 10 years ago), clogging up the entire vacuum system and the engine died within 1 minute of first startup after fresh oil change, the clear silicone hoses tipped me off about the issue in 30 seconds of visual inspection in engine bay, checked oil level, there was the issue, instead of spending weeks disassembling the whole thing while asking on forums/facebook as has usually been the norm, as veterans here can readily confirm.

While you're at it, replace coil, ignition leads, rotor and distributor cap, even if you did it 2 or 3 or 7 years ago these cheap replacement parts just aren't the same quality as OEM replacement parts which can last for over 30 years.

Be ready for igniter to die also, with the abuse it has suffered from those broken wires shortening each other out you just never know, mine has a knack for killing igniters if I leave ignition key on for too long without running engine (no idea why yet) and for yours to last through this kind of abuse is, to me, incredible.