Issues with idle

[JoeliusZ28]

So ive been driving my car since 2008 on the same tune, never had any problem. Last year it started having trouble finding idle especially when slowing to a stop for a light. It seems the car will either high idle around 1500 and eventually settle down, idle correctly at 700, try to idle at 500 and nearly stall or stall, or idle at 550 and barely stay running with the lights dimming and engine making unhappy noises until i intervene with the throttle... In other words You never quite know what youre going to get and i feel like im driving a carbed car with all the dancing i have to do on the gas pedal to keep it happy.

Would this be an idle air valve going bad?

Im considering converting the car to 24x to solve this issue. Even though i could data log the stock pcm too but its time investment getting all that primitive tuning gear setup and running again.

[JoeliusZ28]

My other thought is there is a mechanical issue. Idle rpm isnt the only issue it also doesnt idle as smoothly as it used to. It always had a nice consistent ca-chunka before now it seems like something is a little out of balance like one of the cylinders is short on compression. Maybe i need to do a compression test.

[Atrus]

Dumb question, but any chance it could be a minor/intermittent vacuum leak? Something like a small split in the hose that may leak to a varying degree, occasionally not at all?

Compression test wouldn't be a bad idea, and costs $0 and just a little time. At least it also would give you an idea on where that currently stands.

Given the noise and your suspicion there is another issue that could be causing the idle issue...any chance it could be fuel related? Wonky/dirty injector?

[QuickTop]

Keeping an eye on this my car seems to forget where idle is when in neutral coasting up to a light it will drop down to ~500 and want to stall. a quick "harley-blip" brings the RPM back up and its almost always finds its idle after that.

I always put it off to the mail-order tune.

[JoeliusZ28]

With the fire last year a vacuum leak is certainly possible. i'll have to try the starting fluid trick and see if i can find anything.

[JoeliusZ28]

With the fire last year a vacuum leak is certainly possible. i'll have to try the starting fluid trick and see if i can find anything.

[BlackJesus]

24x swap it and have Phil tune it. Not that thats whats going to fix your problem but the driveability and manners of the car with go up 10 fold.

[JoeliusZ28]

I mean i might just do that anyway ...

figured if theres something obvious/easy im overlooking ill try that first. Forgot to mention the FPR was bad, i replaced that last fall and it only somewhat improved the situation.

[Darren]

driving a carb'd car is fun dont know what your problem is!

[ruckusz28]

So ive been driving my car since 2008 on the same tune, never had any problem. Last year it started having trouble finding idle especially when slowing to a stop for a light. It seems the car will either high idle around 1500 and eventually settle down, idle correctly at 700, try to idle at 500 and nearly stall or stall, or idle at 550 and barely stay running with the lights dimming and engine making unhappy noises until i intervene with the throttle... In other words You never quite know what youre going to get and i feel like im driving a carbed car with all the dancing i have to do on the gas pedal to keep it happy.

Would this be an idle air valve going bad?

Im considering converting the car to 24x to solve this issue. Even though i could data log the stock pcm too but its time investment getting all that primitive tuning gear setup and running again.

I had this happen on my truck. It would bog and go to stall almost every time I went to stop. It was worse when the engine was at temperature. Turned out to be a bad knock sensor. While I was at it, I changed the egr and maf. Runs like new.

[JoeliusZ28]

I had this happen on my truck. It would bog and go to stall almost every time I went to stop. It was worse when the engine was at temperature. Turned out to be a bad knock sensor. While I was at it, I changed the egr and maf. Runs like new.

You know... considering the location of the knock sensor and the fire... that could very well be whats going on here. Would have never even thought of that, thank you good sir!

[ruckusz28]

Keep me posted.

[JoeliusZ28]

driving a carb'd car is fun dont know what your problem is!

Lol amen. my car has always been a little temperamental, and I enjoy driving cars that have "personality." but its not the fun kind of personality when something seems to be wrong

[QuickTop]

find the culprit?