Quote Originally Posted by Jroso View Post
What would you replace first to help fix this problem? The ETM or the ECU and why?
I would replace nothing until I could prove what I was replacing was bad. The car needs to be scanned and throttle plate needs to be tested with Vida for a concrete diagnosis before spending many (more) hundreds of dollars guessing. Someone on your island has access to VIda - you can even buy a black market copy with a dice clone that would help with the diagnosis. (Vida is the software, DICE is a hardware interface between the car and a PC)

That said - the 99-01 throttle units are known to fail. All of them will go bad at some point. Is yours the original one?

I have sold, installed, programmed at least 15 of that style throttle modules. I have never seen a bad ECU on a 1999 and up Volvo. But I have replaced many bad ECU's on other cars - very common were 89-9x 240,740,940- (ecu stops turning the fuel pump on) and a few 93-98 850/s70 for unusual reasons (car stops running sometimes)

If you know you have a bad coil, replace it. Then determine why there are multiple misfires sometimes. (Are you using the factory spark plugs?) As I mentioned earlier the ECU will cut (random) cylinders in response to a sticking throttle plate.