I feel slightly vindicated by your response. I am pleased with the outcome and myself on several counts.
Firstly, despite lively debate and opposition from others it was indeed your over temp light that is flickering and not the injector warning. Total luck on my part predicting that one but I will still take the victory.
Secondly, I am quite pleased that I forecast the faulty temperature gauge following your bridging of the sender. That was pure skill (even though I offered three possible causes).
Thirdly, the fact that your over temp light is still flickering indicates a fault that still lies somewhere, which I also predicted. Smug, I know, but no one will ever say that I don't blow my own trumpet. I hope that this fault is a simple short somewhere though I suspect it may be difficult to find even if it is.
Fourthly, all the talk of over temperature lights and injector warning lights made me get up off my big fat ass and check my own car. I checked my Owner's Manual which once again proved to be no better than reading the SUN. My manual shows that I have an over temp bulb in my gauge but I do not appear to do so. However, it makes absolutely no mention of an injector warning light but I DO have one of those!
Finally, I am happy that the lively debate, wicked banter, doubting & back slapping that the responders displayed has led, by no matter how tortuous a route, to something akin to a useable answer. I believe that it should be a lesson to all who use this forum that the first answer may not be the complete answer. Dig a little further in everything you do, and question everything that you hear. You will not go far wrong.
Please let us know what happens with your emissions and what the reason is for your flickering light.