Chevrolet Trailblazer Stalls with A/C On

Question:
i have a 2004 trailblazer when i turn on the a/c the vehicle idles down even when in driving it so i turn the heater on and it did the same. 2004 Chevrolet Trailblazer.

Answer:
The problem you are experiencing is the engine is not getting enough air when the extra load of the air conditioning is put on the engine. This is solved by a simple procedure. You need to clean the throttle body assembly and that will take care of your problem.

Remove the ducting and plastic air intake that attatches to the throttle body so you can access the throttle bore and blade. Use a good cleaner, brake clean is recommended, and clean thoroughly with a rag. Get inside the bore good and clean the throttle blade too. You really need to make sure you get all the carbon build up cleaned off or you will still have the same issue.

Once finished, reinstall the ductwork between the throttle body and air cleaner and go drive the Trailblazer. It might take a few minutes to get the rest of the cleaner burned out of the system, but after a short drive, the engine will have learned a new idle setting and you won't have it idle down or stall out when you turn on the air conditioning.

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Question:
2004 Chevy Trailblazer. After having the car dealership replace a relay for my headlights, I noticed my vehicle is running slow. Noticed this Friday night two days after taking vehicle to dealer. Once I get around 40, it's hard to increase my speed. On two occasions my truck has cut off while at a stop light with an error message that fuel pressure is low and to stop engine. I just had an oil change on 27 July and my fuel tank was on full both times. Please help before I spend another $300 plus dollars with the dealer!

Answer: There is no such thing as a warning light that says "FUEL pressure low, stop engine". Maybe you mean oil pressure? If that is the case then you need to check the oil level and have the oil pressure of the engine checked. It could just be a problem with the oil sender switch telling the computer that pressure is low, but is is really not. Or you could actually have low oil pressure. That would need to be confirmed by installing a gauge and checking.

This can cause the acceleration problem or it could be a different problem. Low fuel pressure- which has nothing to do with the amount in the gas tank.

Question:
When i turn on my a/c and let it idle the rpm dips way below 1 and almost shuts off until i rev it up again but if i let it sit there it shuts off, it does the same thing when i turn on the heat, other than that the engine is fine, but only when the a/c and heat get turned on it starts to die, i just changed out my battery as well so i have a new battery, also with that my power buttons on my door don't work from time to time, and i wonder if they are related to each other. Chevy 2003 Trailblazer.

Answer:
OK. This is a very common problem when there is carbon in the throttle body bore and plate. Suggest a good cleaning. The throttle body is the front top of engine that the air cleaner duct hooks up to. Remove the duct, open the throttle blade, spray some carburetor or carbon cleaner from any parts store all around the bore and plate. Then spray some on a rag- not a paper towel, and wipe all around the bore and plate. Re-install duct and start the engine. It will run rough for a few second. Rev it up a few times to "Clear it out". Then take for a short ride doing a few hard accelerations. Shut truck off for 2-3 minutes, then start ans let idle. After this, the idle should be fine." The window problem may be in the switch itself. If this is the problem, a new switch would need to be programmed after replacement.

Question:
Tune up the truck replaced everything back i had to disconnect the resonator and connect it back to reach spark plugs when i start it runs smoothly but when i turn on the ac rpms run low, engine shakes, stalls, then powers up and stalls again then finally dies with the fan still blowing. I took it to check battery and alternator i got a diagnostic and no warnings popped out everything was good so no idea what is wrong why does it die after i turn on the ac? 2005 Chevy Trailblazer. Repairs made- air intake temperature sensor and throttle body cleaned.

Answer:
It is stalling out when you turn the A/C on due to the engine not getting enough air when the idle raises to compensate for the air compressor kicking on. This is almost always fixed by cleaning the throttle body. If you already did this, you didn't do a good enough job. You have to really get in there and clean around and behind the throttle plate. Any little carbon left behind will still cause issues. You should take the air intake off again and re-clean the throttle body really good with a product called 'brake clean'. After reassembly, start the vehicle and rev it up to burn out any excess cleaner, and then take it for a drive. It will take a little bit for the vehicle to re-learn the idle again, but it will be fixed after that.

Question:
I start the engine, when a turn the air conditioner on the rpm dips or the engine shuts off. The idle don't stay normal.

Answer:
The problem you are experiencing is very normal for these vehicles. What is happening is that there is an airflow restriction at the throttle body due to carbon build up. This occurs over the years as a result of bad gasoline, hard driving, lack of maintenance, etc. What you need to do is remove the air ducting to the throttle body and then with a good solvent based cleaner, clean the throttle body very good including the throttle blade and all inside the throttle opening.

Most auto parts stores have a good cleaner for this purpose. You really have to get in there good and clean extremely well to solve this issue. If you have compressed air, that be a help too in drying out the throttle body after cleaning. Once it is clean, reinstall all the ducting, reconnect any sensors, etc, and start the vehicle. If you got any cleaner inside the intake it will burn off almost immediately, but can cause the vehicle to run rough for a minute. Once the vehicle has reached operating temperature, take it for a short drive. This is required so that the computer can 'relearn' a new idle speed. After that, you should be able to use your air conditioning, defroster, etc, without any problems at all.


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