Engine light on and chugs going up hill no more than 20 mph

Hi, what do you mean by chugs at 48 mph ? Doesn't it go any faster then 48 mph, does it lose power, bog down when you press the gas pedal to the floor. Does it have a misfire , that makes the vehicle buck and jerk ! Is the check engine light on or any other lights for that matter ? How many miles are on this trailblazer ?

Sounds like you are getting too miuch fuel and not enough air. Try replacing your spark plugs and wires, then cleaning your throttle body. Replace the air filter too if its been awhile. This will probably fix the problem.

Better check your codes again sounds like your converter is plugged up

Hello,

A bad cat will glow when vehicle is at normal operating temperature.
vaccum leak, tune-up?

If you mean the engine starts running rough at say 40 or 50 mph, once you go into overdrive the engine is working very hard and any weak component can show up. Could be spark plugs or other factors.
If the check engine light is on you need to have the computer checked for trouble codes to help narrow down the options.

The first thing that comes to my mind is "45 MPH"... and let me explain why.....

Your engine you said is running GREAT so a MPH is not going to effect the running of the Car but what happens @ 45 MPH you ask?

Your Torque Converter goes into Lock up.... If the Torque Converter is slipping in and out of lock up, you are going to have an irregular pulsating of the engine playing catch up.

you need to do this, try and drive the vehicle (you did not say what kind of vehicle it is), and drive it without the OVERDRIVE On...

So drive it and see if it is RPM RELATED. If there is no CHUG and you can go all the way to 55-60 without issue, Slow down below 45 and put the OD IN and accellerate and see what happens..

Is the Problem SPEED RELATED? Is it RPM Related?

If it does not happen with it OUT of OD, then what you probably have is a Torque Converter Failing...

I hope this helps

It is usually coming from the spark plug wires( leak spark). Spark to ground or piece of metal.
To find out exactly take an empty spray bottle fill her up with water and add 2 tablespoons of salt. With the engine running a light spray of the mix on spark plug wires you will see the spark leak and proof the spark plug wires have a defect. if so replace all spark plug wires that should solve your problem.

Hope it helps.

although the check engine light goes off, the code is most likely still locked in. stop by your local advanced auto parts, or mechanic to have them check it out.

if its a petrol get coil packs cheked does it do it under load mor when accelarating ir pulling up hill this would cause it to miss

starts missing after it warms up and on take off after a stop