Hey all, as of the past day, I suddenly have a strange problem that I'd like help with,it's in the title but yeah. Rough idle, searching for idle a little bit too. Going from 500-400 while in drive. She shakes heavily on takeoff and under load. I'm thinking it's the engine mounts, but I also think the motor is ready to junk lol.....I can give more details so please ask if you are curious about anything!

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Checked for cylinders missing ? How are tuneup items ?

 

I don't think I have any dead cylinders, tunup items...i assume means usual maintenance? Oil and plugs done recently like, 2 months ago (actually). I did break a plug wire but I definitely fixed it....how can I test it if it stopped working again?

 

Plugs, plug wires, cap/rotor. A bad wire or bad cap can cause a cylinder miss.ohm wires, i assume tpi can pull injector plugs one at a time see if they all drop in rpm when unplugged. Or use plug wire pliers to start pulling wires off the cap listening for rpm drop. What steps have you taken to diagnose?

 

so far I've done the basics, check fluid. Everything checks out. As of now, i just changed my plugs and the problem persists, now im going to change my ignition coil. Last month I checked my injectors with a voltmeter. All 16ohms so it's good there. I can't just pull the injectors I'd have to remove the entire intake and fuel rail to get a look at them.

I have noticed that on first startup it is not an issue, then i let the rpms settle and drive a few feet and it comes up.

 

chabged out ignition coil, same luck. I'm going to check my motor mounts tomorrow though....

 

It definitely doesn’t sound like a coil breaking down. Good luck with the parts canon.

 

yeah, I'm trying everything. I had to do the transmission mount when i got the car so maybe it figures my engine mounts **** the bed

 

If its motor mounts... It wouldn't effect the way the car is idling...

I would second what Tuned recommended and start pulling injector plugs, or checking spark plugs and wires one by one to find your culprit. I have put brand new spark plugs in my car and had a misfire, little did i know one of the porcelain housings was cracked and causing a misfire. I only noticed it while checking under my hood at night, I saw the spark arching. I would also check your Throttle position sensor voltage to see if maybe that is going out as well. No need to throw money at the problem, because you don't actually know what the problem is. I remember when I bought my first Trans am almost 15 years ago, everytime I had an issue, i would just start replacing all kinds of random parts and that got expensive fast and almost never fixed the issue. Take the time, do some cheap and easy testing first and diagnose the issue. I guarantee Motor mounts is not causing your rough idle and hesitation under acceleration.