Poor preformance

[DLP]

I had the trans rebuilt this spring. I had a backup trans that I broke the pump while installing it. A lot of time and money for nothing. Anyways, the truck never really seemed to have the preformance that it use to. It also ran a little hotter than useal. So I did a complete tuneup . About 8,000 miles later I had a miss caused by a bad spark plug boot arking to the manifold. So I replaced the one boot. A couple weeks ago, my son and I were hauling our quads north in the rain and the truck started missing at low RPMs. I pulled into a Carquest and changed out the cap and rotor again. Didn't make any difference. So we limped home. I couldn't keep the RPMs up in OD. So I came the 200 miles in third. Got home and pulled the plugs. All looked good. They should with only 10,000 miles on them. I ripped most of the boots while pulling them off. So I replaced the wires and all seemed good to go. The motor ran smooth. But wouldn't carry OD most of the time on straight roads. So I opened up the precat and gutted the crumbled, melted mess out. Welded it back shut and thought I had it made. But after a short test drive, there was no difference.

So today I pulled the Y pipe on back off. I took the tin cover off the cat and turned it upside down. Cut a access hole in the top and pulled the comb out. It was clean and clear. But there was a lot in the front from the precat. Welded it back close and put the tin shields back on. Bolted it all back togather and took it for a run. Haven't had it on the hiway yet. But it will now squak the bigger tires. I was having trouble scratching off on gravel. It was in the mid 80s and the temp stayed right at 195. I also changed out the fuel filter for good measure.

Sorry about the long post. I have spent a lot of time trying to figure this one out. I hope I got it.

[HenryJ]

Sounds like you did. A plugged cat can really mess things up. Was yours still eligible to be warrantied? Isn't it 12 years and 120k miles now? Or was the mileage unlimited?

[DLP]

Not sure. I have 153,000. I will find out this weekend when I head north for bow season.

[DLP]

Life is good! My truck is running and sounding better than ever. After gutting both cats, the power and preformance has returned. But after a couple weeks, I could no longer stand the tinty exhaust sound. So the truck now sports a 3" Magnafllow muffler with dual exhaust. I replaced the cats with a 3" straight pipe at they Y. Than ran 2 1/4" pipe back and exit behind both rear tires. It sounds great. Defently turns heads. But doesn't sound like an exhaust leak. More like a deep tone big block. I got the Magnaflow for $100 and the pipe for $50. My friend has a station and let me use his bender and welder. Going to install one on my son's Elcamino this weekend.

I now have about 1200 miles on the new exhaust. Gas milage is up to 18/19 hiway. Not as good as it was new 20/21. But a lot better than the 14/15 I was getting before the swap and gut. I might get better milage if I quit listening to the sound and keep it under 80 on the hiway. But it just seems to run with less work.

As for setting off SES codes. I get one about every 2 to 3 fillups. With the Scangauge, it only takes 10 seconds to clear it on the go. Sure wish I would have done this a couple years ago when the gas milage started dropping off.

[killian96ss]

I'm sure your aware of this, but I'll mention it anyways. It is a federal violation (illegal) in all 50 states to remove or alter any part of the emission system, especially removing the cat. If your state has any sort of visual inspections and/or emission testing, you will fail either one without a cat in place.

I really dont see any reason to run without a cat. They are already high flow, so there is no loss of horsepower by using one, and using one drastically reduces tailipipe emissions which helps keep the air cleaner for all of us.

Just my

Steve