1-2 bang shift, try a TSS. Not easy to put in if the car is northern, tends to corrode in. Plugs should be changed with the appropriate double platinum type, by now your plug gaps will be too wide. Take one out carefully and take a look. Caution: aluminum head. If it looks good and gap OK, you probably don't need plugs. Try this topic for P0171:
P0171 ZetecSearch P0171 Zetec Maintenance all posts. Vacuum leaks are cheap to fix, harder to find. Look for cracked or unplugged hoses.
