Help needed
Thread Starter
3rd Gear
Joined: Jul 2022
Posts: 3
Likes: 0
Help needed
I have a 1990 C4 convertible. It is having an idling problem. When Air Conditioning is off and vehicle is in Park or Nuetral idling is pretty normal. When it goes into Drive or reverse the car starts to shake and idling becomes sluggish. It gets even worse and shaking gets worse when the Air Conditioning is turned on. Does anyone know what could be causing this and how to fix? P.s. Car also many times will start to miss and get sluggish around 50 mph and stop around 70mph. Does not happen all the time. I did check fluids today and noticed it was bone dry on coolant. I added more today. Any help is appreciated. Thank you!
Instructor
Joined: Jun 2022
Posts: 194
Likes: 47
Sounds like you have several problems. You must fix that coolant leak first. Fill with water and get a pressure tester and pump it up and find where leak is. Did it ever overheat? Pull all the plugs and see if they are all burning the same. I assume no engine codes or you would have mentioned that. When you get car running, get a can of carb cleaner and start spraying for vacuum leaks.
Last edited by pete315; Jul 30, 2022 at 03:58 PM.
Zen Vet Master Level VII
Joined: Mar 2016
Posts: 5,218
Likes: 1,174
From: Southlake, TX
How many RPMs is your car running at idle? If too low to begin with, shifting in gear or the additional drag of the AC will "pull it down" and make it run lump.
Did you run the engine coolant dry or was the overfill tank empty? Either way as Pete315 said, this needs to be your top priority.
Yes, check for vacuum leaks, but typically a leak will give you a higher than normal idle.
Did you run the engine coolant dry or was the overfill tank empty? Either way as Pete315 said, this needs to be your top priority.
Yes, check for vacuum leaks, but typically a leak will give you a higher than normal idle.
