Stalling and Limited RPM

Badaxe · 03-31-2014, 10:01 PM

So just over the past few weeks my 2.4L has started to bog pretty bad at traffic stops to the point where if I don't put it into neutral it dies. You can only imagine how frustrating a recent 30-point turn was the other day. when I'm moving it seems to run pretty smooth. Did find a vacuum leak on the TBI, fixed it. Latest finding is that in park or neutral it will only rev to 4100-4200rpm and then sound like a rev limiter. When running through the gears, pedal down, it will run into the 6000rpm range no problem.

Suggestions? I'm already thinking motor mounts maybe?

rustyballs_69 · 03-31-2014, 10:11 PM

In park and neutral it won't go over 4200, safety so you don't pop your motor.

rocketfast321 · 03-31-2014, 10:14 PM

4k is the rev limiter.

First how many miles and what codes does it have.

[ion] C2 · 03-31-2014, 10:17 PM

Quote:

Originally Posted by Badaxe

Latest finding is that in park or neutral it will only rev to 4100-4200rpm and then sound like a rev limiter. When running through the gears, pedal down, it will run into the 6000rpm range no problem.

The tune is set to fuel/spark cut around 4000RPM in P/N and 6250ish in D.

Quote:

Originally Posted by Badaxe

Suggestions? I'm already thinking motor mounts maybe?

Has nothing to do with it.

Pretty sure you have a good sized vacuum leak. Either at the intake manifold gasket, throttle body gasket, or one of the hoses.

Surely you checked the spark plugs, air filter, stupid stuff already.

Badaxe · 03-31-2014, 10:43 PM

Plugs have less than 6K on em' and engine is at 145K. Good to know the rpms are doing what they are supposed to. Came up with the motor mount "approach" from other posts here.

03glgold · 03-31-2014, 11:48 PM

Map hose? Exact symptoms of my friends when it was acting up from that

Redog · 04-01-2014, 03:30 AM

ICM.

Spend the money and get an ACDelco one

sleepyalero · 04-01-2014, 04:28 AM

Or maybe an IAC?

icm on that motor I believe is connected with the IDI Cover. Its a decently expensive fix

03glgold · 04-01-2014, 08:03 AM

I would start cheap with the suggestions and work your way up the list

[ion] C2 · 04-01-2014, 09:06 AM

Quote:

Originally Posted by Redog

ICM.

Spend the money and get an ACDelco one

If it was an ignition module problem it shouldn't go away at high RPM, it'd get worse.

Vacuum leaks tend to cause issues at low throttle far more than higher. IAC, TPS could also be of concern, but vacuum leak is more likely than anything else by far.

Redog · 04-01-2014, 09:01 PM

It's just that the issues he mentioned reminded me so much of the problems I had.

There is no vacuum present at WOT either. So yeah look there first

Badaxe · 04-01-2014, 10:30 PM

Thanks for the advice y'all. I won't be able to touch it until tomorrow afternoon so I'll let you know what I find.