Hello, I’m searching for help for my 04 ls blazer, I put in a cai and it was working phenomenally until a couple of times I had a lot of trouble reaching 55 mph. I figured if I put my old stock air intake and filter it would fix the problem, I was dead wrong. Now I’m having trouble reaching 25 mph and can’t get above 2500 rpm my obd said it was the maf so I replaced it and the same issue. I’m hearing a lot of talk about a bad Cadillac converter but I’m at a loss currently. Even when I try my best to give it a bit more throttle my rpms die. Any suggestions or ways I can troubleshoot my problem would be helpful, Thanks!

 

There are a couple of ways to check for a clogged catastrophic converter. You can temporarily pull the upstream O2 sensor out to see if it runs better, since that will relieve the pressure. you can also put a vacuum gauge on it (or watch the MAP reading on the scanner) and run it at about 2500RPM in neutral. If the converter is clogged, the vacuum will steadily drop off.

It would be a good idea to put a fuel pressure gauge on it, too, so you can see if fuel pressure is dropping when you lose power.

 

I had the same problem on my 05 ZR2. Removed the cats and was able to solve the RPM issues.

 

What code did you get? Knowing exactly would help. If you oiled the CAI, the MAF sensor may not be operating properly and needs to be cleaned. Also check the tiny little resistor wires in the MAF sensor. They can be broken and hard to notice. I use a loop with my older eyes.

Check your IAT sensor real close and make sure you it didn't break (though you should get a code for it) or is soaked with oil from the CAI (if you oiled it).

Some auto parts stores have a loaner back pressure tester that has the adapter for the O2 sensor hole. You'll install in place of upstream O2 sensor (before cat). During cranking you should have 0 psi pressure. At idle should not go above about 1psi, at 2500 rpm should not go above 3psi. As mentioned many vacuum gauges will work also since they show low psi readings as well as vacuum, but you would might not have an adapter. AutoZone at one time loaned them out. The part# was 27263. If you read above the pressure readings, you have a clogged exhaust. Could be your fuel trims were to rich from bad sensor input and burnt up the Cat.