Here's the story yesterday I removed all of the smog equipment and I capped the hose going to the cat. And then after that it started backfiring every once in a while and there is a lack in power. Also, it vibrates like hell. What are you're suggestions. I replaced the egr valve about six months ago so it shoudn't be that. I checked all the wires to make sure they are tight.

 

After removing all the smog equipment, does the ECM have any stored error codes?

 

Sound like a loose or defective spark plug wire, or broken spark plug, or 2 plug wires swapped.

Look over everything you touched. Odds are, there's a mistake in there somewhere (in addition to the mistake of your actual task).

 

I checked the wires and the # 2 and # 4 wires we're switched. Thanks so much for you're input RB83L69.

 

That would do it....

I learned a long time ago, that if something worked before I touched it and it's screwed up afterwards, I probably did something wrong. As humbling as it may be to admit to myself that I might make a mistake, it's still the first exercise I go through, when something like that happens.