Hi everyone-
Noob here. I'm planning on having the local AutoZone scan the car for me, but wanted to see if anyone had any insight here as well.

I have a 1999 Suburban that I use to tow my 2-horse trailer. I only haul my horse, so the trailer isn't terribly heavy -- less than 4,000 lbs when he's on with my gear. (Put it this way -- my trailer brake connector came loose this morning, and I was able to stop the trailer easily with just the Suburban to fix it. ) I believe the max towing capacity on the truck is around 6500 lbs, so I'm well under weight. It's also equipped with a cold air intake and transmission cooler, and I've never had an issue with the tranny overheating.

Occasionally I'll feel like it's a bit anemic to tow with, though, and I'll be driving along (~55 mph) and the truck will start to shake/shudder. If I let up on the accelerator, the shaking usually stops. This only seems to happen when I'm towing the trailer, so naturally my first reaction is .

Today I was driving along the highway and was going up a gradual grade. The truck downshifted, as it usually does when it needs power, and got some minor shaking. I kept going and all of a sudden the CE light starts flashing and then stays steady. It's still on, and I'm wondering if the shaking has anything to do with the CE light.

Any ideas why this would be happening? It has about 178k on it, and the previous owner took VERY good care of her... but I've put a lot of $$ into some fixes (new front/rear gas shocks, new brakes all around, just had the master cylinder replaced, etc.) and feel like I've got a money pit...

Thanks in advance!

 

Welcome to the forum. The flashing malfunction indicator means a condition that will damage the catalytic converter, like raw fuel out the exhaust from misfires. With high mileage vehicles misfires can actually be caused by restrictive exhaust from plugged-up catalysts. It's just something to think about but the diagnosis has to start with the trouble code and freeze frame data that goes with it.

 

If it has a torque convertor lockup clutch, it might be the culprit for the shake/shudder.

 

Thanks everyone! I drove it to a nearby show on Saturday, and the light was on when I left the barn and arrived at the showgrounds... about 4 hours later, I started the truck back up to go home and the CE light had gone off. Weird. I'll still have it looked at if I get the chance.