My beloved '87 Volvo 740 Turbo wagon behaves strangely after my repair. Here the story. My timing belt came off - I didn't know that you should also change the belt tensioner bearing when I changed it 30km ago at 200km. Anyway, so the crank- and camshaft position was messed up. I successfully put everything together except I messed the spark plug wires up - cylinder 1 had the cable of cylinder 2 and vice versa. So when I started, cylinder 1 or 2 misfired (remember my cable mix-up). So, now I have these symptoms:

1) During acceleration I have a mechanical sound when my pressure/turbo gage gets into the yellow area but stops around 1 o'clock position (so at full acceleration I don't have this sound). The position of the piston 1 is in TDC when putting on the timing belt. So either the intake or exhaust valve was open when in misfired (??) I'm afraid that one or more bolts of the exhaust/intake manifold are broken off (had this already and it was not a nice job at all!!) But at this time I had this sound also at high pressure. I also checked the bolts and they seem to be ok. So I have no idea what it causes (maybe turbo or throttle valve??)


2) When the engine is cold and I go off the gas pedal, the rpm drops fast in one move to 1700 rpm and from there on very slowly to idling. It didn't behave like that before my repair. It came down in one smooth move. When the engine is warm this doesn't occur.

3) Driving down the hill and using the engine break my pressure/turbo gage stays at idling position - before my repair the needle was below because of higher sucking of the engine. So, I guess I got somewhere a leak in the intake?? That’s maybe a sign that I got too high pressure (because of the misfire) on the intake side??

The engine runs nice (except the mechanical sound and these little details). Am I just super nervous and see already ghosts???
Thanks for all your help (brickboard helped me to figure out that my timing belt came off and not that I had a ignition problem).