Sometimes those valves LOOK like they are opening all the way and when you look thru them you find that they actually are not opened as you thought…yeah, start there… an IR thermometer would come in handy yet again…don’t know how many x I have mentioned this tool on here…but its A LOT I can tell you that. The IR thermometer costs bout 20 bucks and is well worth it…Harbor freight…and most auto parts places now have them…
Blackbird