2001 Cadillac Seville SLS Q&A
2001 Cadillac Seville SLS Question: Service engine light keep popping up with error code P0171 and P0174.
Repleaced MAF, PVC, air filter and checked for vacuum leak and found none. This weekend I am going to replace the Plenum boot between the intake manifild and the throttle control to make sure there is no leak. When I raised the engine RPM pass 4000 I can feel one valve missing during the firing sequence. Appreciate your help on this. - ranjit
this code can be very tricky to diag and repair at times. you most likely have a vac leak and on the 4.6l the boot does crack between thottle body and intake.when you remove it look on the bottom for small cracks or holes. if its ok i rec you get a smoke test which will show any vac leaks you have. ps repl the boot since it will be off and is suppect to leak at times - globalhelper