when i start my f150 1990 i get a eratic idle my truck almost dies. i have also noticed a loud ticking noise when it does this. when i drive it and then let it idle the loping begins agin. it also seems to mis under load

thank

 

Hello Sofakingphat,
Check for a loose sparkplug. If they are okay then the loud ticking could be a dirty lifter or worse case a collapsed lifter. The fact that the engine is running crappy also indicates a bad lifter or sparkplug. It's possible that fresh oil, filter and maybe an additive like Slick 50 might un-stick the lifter. I have used crankcase flushes in the past but don't anymore cause I personally know 2 guys that did flushes and within a month the rod bearings were knocking but it's your choice. I never hurt my engine and it might do the trick. You can use a vacuum gauge to test for a stuck lifter but I don't know where the manifold vacuum port is on your motor. Anyway find the port and connect the vacuum gauge and it should show a steady reading of 18-20 at idle. A stuck lifter will make the needle jump every time you hear the tick. Good Luck