98 f150 runnin bad @ idol

my 98 f 150 V8 4.6L "W" lost power and now has a bad miss. got codes po308(#8 cyl. missing[changed spark plug]) no help. code po171(lean bank one[replaced drivers side o2 pre cat])no help. code po174(lean bank 2[replaced passenger side o2 pre cat]) no help. Also replaced MAF. Checked coils they were ok. Plugwires ok. Runs well at 2000rpm drops to idol shakes profusely. Need help or ill have to take it to the dealer.:banghead:

my 98 f 150 V8 4.6L "W" lost power and now has a bad miss. got codes po308(#8 cyl. missing[changed spark plug]) no help. code po171(lean bank one[replaced drivers side o2 pre cat])no help. code po174(lean bank 2[replaced passenger side o2 pre cat]) no help. Also replaced MAF. Checked coils they were ok. Plugwires ok. Runs well at 2000rpm drops to idol shakes profusely. Need help or ill have to take it to the dealer.:banghead:

We had the same exact problem. Except we have the 4.2 V6. We found out that we had a leaky seal in the engine and it was leaking water into the engine.