2000 Blazer very sluggish on initial take off. It does this in reverse and drive. It will do it after being shut off for five minutes or all day. It does not do it after it has been idling for any amount of time, only after being shut off. Just replaced catalytic converter and it continued. Check engine light still on also. Any ideas on what it could be?????

 

I would start by having the codes read and let us know what they are.

After that, I would recommend a MAF sensor cleaning. Overtime, the MAF sensor can become diry and compromise it's ability to feed the proper airflow reading to the PCM. This is amplified by the use of an aftermarket oiled air filter (K&N for example). If you run a search on 'MAF cleaning', you should find the procedure, but please let us know if you have any further questions.

 

As a matter of fact, it does have a K&N air filter. My husband will try cleaning the MAF and maybe that will work. He is also in the process of getting the codes read.Will let you know what they are. He also replaced the spark plugs today. Thanks for yourhelp.