Having A Rough Time

[BNICHOLS118]

Just put new jasper engine in ran find the first 800 are so miles.Now when I crank up in the morning truck runs great{But when you get out let it sit 10-20 minutes and come back out it acts like it's running on half of the cylinders].I've put new egr valve,egr sensor,cooling sensor,map sensor,when it does this and you drive it will miss and seem to try to catch up.I've notice while driving in rain it seems to run better any ideas I sure would appreciate.

 

[Broncoholics]

I'd first look at each spark plug and see if any are fouled out. If you have points take a look there. You can do a air leak down test found that my valves were leaking. It would run decent until it warmed up then it would he a rough runner. So add some air pressure into each cylinder and see it it looses air pressure. I could hear it leaking into the upper galley. I had case hardened valve seate put in and it runs great. Sometimes you can find it with a compression test as well.