p171 code and po305 99 winstar (HELP)

[pierce76]

I took my van over to Autozone and got the diagnostic check done and P0171 and 305 came up. Now my van has only 74000 miles. Lately it has been running rough and sorta bucks every now and then. It did this about a year ago and I changed the PCV valve and plugs/wires and the van has been running great until now. Its starting to do the same thing. Ive been reading about the TSBs for thr 99 and 00 but havent been able to download them. The ford dealer said you cant go by autozones codes and they would have to see but it sounded like a possible vacumn leak.

I just had the "3-step" feul injector cleaning and still runs rough. Should I change the plugs again (its only been 30000 miles). I am going to get the fuel filter and air filter changed and possibly the IAC. I hope someone can help. I would appreciate it.

[rivguy]

0171 is lean bank 1 and 0305 is cyl 5 miss (center cyl. rear) - my question is does the bucking go away when the vehicle warms up?

[pierce76]

Actually, sometimes it may buck in idle and going down the road. Does it eventually go away...no...although it has been running good today with no bucking at all...go figure.

Im going to replace the plug wire and #5 plug to see if it works but I think its a vacumn leak or the beginning stages of one. I went to Ford today to enquire about the TSB for the gaskets/valve covers etc on the 3.8 and the service mgr said that program died two years ago. So it will cost me about 600-700 dollars to fix.

Last time it bucked, I replaced the plugs and it ran fine. But that was only 30000 miles ago. Any suggestions would be greatly appreciated.