engine can't handle load...

**gotboost3** · 05-01-2009

ok guys i know i have a vac leak that is causing an unsteady idle but i noticed something odd today...any time an acc is used on the car at idle my engine plummets to 450 rpm, for example if i turn the wheel at idle (powersteering) the rpms drop instantly, also when i switch on the headlights my rpms drop too, just my headlights....weird, anybody know what would cause this?

TDCRacing · 05-01-2009

Sounds like your IAC might be bad or may just need a cleaning. The IAC compensates for things like this such as when the A/C comes on or a load is put on the engine while running. But only when it is idling or close ot it. When the RPM's go up the IAC cuts out. All it is there for is to keep the desired idle set by the PCM in the correct place.

**blueguy** · 05-01-2009

Could it also be the alternator is taking a crap? I had symptoms like this too when it wasn't charging...might have it tested...just my 2 cents.

**Sabrewings** · 05-01-2009

With a vac leak, it's hard to troubleshoot other symptoms. Fix that first.

**gotboost3** · 05-01-2009

ill clean my iac asap and i used to have a loud system that abused my alt so maybe thats it....ill check to see if i get voltage drops when it dips...

TDCRacing · 05-01-2009

Originally Posted by gotboost3

ill clean my iac asap and i used to have a loud system that abused my alt so maybe thats it....ill check to see if i get voltage drops when it dips...

Your going to get voltage drops when the idle dips. It's putting a strain on everything. And that's why your loosing idle speed. knowing the other problems it's not going to be your alternator. But that's just my .02

**gotboost3** · 05-01-2009

ok thanks would a vac leak cause drops at specific times liek that or is that most likely a IAC problem?

**Sabrewings** · 05-01-2009

Originally Posted by gotboost3

ok thanks would a vac leak cause drops at specific times liek that or is that most likely a IAC problem?

Any time you have unmetered air entering the engine and the load changes, odd behavior will occur. You need to fix the vac leak before you can trouble shoot something else.

**gotboost3** · 05-02-2009

Originally Posted by Sabrewings

Any time you have unmetered air entering the engine and the load changes, odd behavior will occur. You need to fix the vac leak before you can trouble shoot something else.

ok thanks man im stil hunting down this leak i think its a bad sc gasket....because mine ripped when i took off the blower but i still re used it because i didnt have a new one at the time....would you say thats prob it?