Problems with high idle after stolen catalytic stolen.

1st time post, long time lurker. I had my cats stolen and had replacement cats and downstream o2 replaced after stolen. A week later <100 miles my battery died and after replacing the battery truck has a high idle. Battery was old and wouldn't hold a charge. 1 start fine. 2nd start after a 50 mile drive and setting for 12 hours its gone wacky. Truck idled between 1300-3000 rpm. Drove home and something obviously was with not right. I'm not a car mechanic but do have mechanical/electric knowledge. Any ideas? 2006 double cab sr5 4.7L. This is not my main mode of transportation as I drive a work vehicle daily. I have a good repair shop just trying wrap my head around this. Thanks in advance.

 

Many have reported our 1st Gen Tundras don't get along well with non-OEM cats. Although apparently the Summit Racing 3" performance cats will work.

That said, which cats did you get?

And how many miles since replacing? Many of us have observed the truck running wonky after clearing the ECU of all codes, until the truck finishes a full test cycle, which can take days and hundreds of miles. Edit: I mention this b/c if your battery tanked, it may've reset the ECU, causing it to need to re-calibrate, which can be a rocky road, especially w/non-OEM cats and/or O2 sensors.

Also, which O2? These trucks are extremely sensitive to O2 sensor brand. Go Denso.

And NEVER NEVER NEVER buy from scAmazon, fleaBay or WallyWorld. Huge counterfeit parts risk, many have been burned!!

 

I had a high idle problem after having removed and cleaned my throttle body (and replacing the MAF with new OEM).

I disconnected the battery, then it took about 1 day, and a dozen or so engine stops/restarts until the ECU relearned.

 

That's all these trucks take, especially for minor maintenance issues, which may be all that's needed. Agree wholeheartedly with all three above, especially the OEM comments by @shifty` and @w666 long drives/recranks so the ECU can relearn a clean system.

According to when you accomplished these minor maintenance issues, I'd suggest checking or changing with OEM....

1 air filter
2 clean MAF sensor and Throttle Body(TB) with CRC MAF cleaner/TB cleaner
3 spark plugs - properly gapped

Any videos/literature needed to accomplish these basic maintenance tasks, can be supplied !

 

On this one - 2006 here. Should be using Iridium plugs. Iridium plugs should come pre-grapped, manually gapping could damage the plugs.

I know you know this already, but OP may not know it already. Specifically that Iridium plugs should be used, and/or that you can't (well, shouldn't) gap iridium plugs.

 

All plugs, that I've had experience with over the years, come pre-gapped but have and will always check that they are still gapped properly even if only visually, regardless if their iridium. Items do get damaged in transit but I know you know that already. The OP needs to at least visually check IMHO.

 

I don't disagree. Just remembering this case from a few weeks back, I'm not unconvinced OP over there didn't have a case of someone physically gapping iridium plugs there, bending the electrode.

Denso has a good page dedicated to tips on Iridium plugs, and general plug install, maybe helpful with OP making a point of saying he's not a car mechanic.

I always gap old school fatty-electrode plugs. Iridium tips are too damn easy to bend.

 

Update on my idle issue. Cleaned the throttle body and reset the computer by disconnecting the battery. Now after about 100 miles of driving back to normal. So aftermarket cats and o2 sensors seem to be working properly. Thanks to all for the input.