I have a bit of a strange problem. It's been going on for a while but it's just now starting to really bug me.

When I'm on the interstate and cruising at or below ~2300RPM, the car runs fine, but if I go over that then I have some problems. The SES light starts flashing, I lose power (as in it boggs down, not loss in electrical power), and there is a bad smell. This normally happens going up a hill but a few seconds when I get over the top, I regain power, the light stops flashing, and the smell goes away. It happens on level ground also if I run the RPMs up so it isn't directly associated with hill climbing.

I've had the car for about 60,000 miles now and it's been doing it for the last half of that or so but I'd like to get it fixed so I can go faster than 65MPH. Anyone know where to start or had a similar problem? It's just strange since it runs perfect otherwise.

Thanks in advance.

 

Sounds like a misfire being detected by the PCM and turning on the SES light. Lots of things can cause misfires. Fuel related, electrical related, engine mechanical related, exhaust related.

Are you committing to doing the work yourself and obtaining the tools necessary to complete the job? know that it is seldom the case where there are easy answers. You will have to do your part.

If you are committing, please get an OBD2 scanner that will display both the misfire counters and CMP retard. Don't assume some generic cheapo scanner will do it.

For your 2001 vehicle, I recommend either Car Gauge Pro ($8.95) or Dash Command (2 x $10 with extended GM PIDs) - both Android apps in Google Play. Also you will need a Bluetooth OBD2 adapter - recommend the BAFX one as sold on Amazon ($23).

If you have Iphone, then Dash Command is available for that OS, but you will have to punt to find a WiFi OBD2 adapter (Bluetooth will not work for anything but headphones thanks very much to Apple).

Get this capability then come back and we can get started. Otherwise, the only thing anyone will be doing is to guess.

 

Your symptoms fit the bill for a bad catalytic converter. That's the first place I would look. The easy checks are to visually check it for damage and bang on it with your fist to see if it rattles. There may be other issues that caused it to go bad. But I would start with checking out the cat.