Aspire dies when dropping revs

[TominMO]

My Aspire has one quirk I have been dealing with for awhile. With the motor warmed up, if I am driving along at normal RPMs like 2500+, then shift into neutral, the revs drop to the point where the motor dies. But if I decelerate in gear to maybe 1500 RPM or less, then go to neutral, it will drop down to below idle speed and then come back up and idle. These behaviors are consistent, not occasional.

Any thoughts as to why it is doing this?

[FestYboy]

Lazy IAC would be my first suspect, the next would be poor MAF signal.

[sc72]

^^ as Arty said, lazy IAC, I pulled mine off about a month back with the same symptoms, cleaned with Dawn Power scrub, rinsed with brake clean and aint life grand, it works and no low RPM stall. Good luck

[TominMO]

^^ as Arty said, lazy IAC, I pulled mine off about a month back with the same symptoms, cleaned with Dawn Power scrub, rinsed with brake clean and aint life grand, it works and no low RPM stall. Good luck

Wow, never heard that diagnosis--"lazy IAC". :-) I'll file this away and deal with it when it warms up in a few months. Right now I deal with it by blipping the throttle as the needle is on its way down. But sometimes I forget. Thanks guys.

[harpon]

If it's not electrical component- run carb cleaner/injector cleaner petroleum distillates

at all times

or as much as possible- still just a buck at dollar stores

it really works to keep bogging injectors and gummy fuel system clean

I just put a new filter on the 91 festy and kicking myself for not filling the line toward injectors with spray cleaner

also- in gas tanks that sit idle- the light part of the gas evaporates over time, leaving a greater concentrate of gum in the system

the distillates even out the mix again

a better grade of premium gas is supposed to do the same thing- not sure it does, but yu could try better gas to see and maybe blow some gum away

[Greywolf]

My '91 does that, and to an extent the B6T car did before I put it in the shop for the winter(?) so that I could do an in-depth on it.

A lazy or partially sticking IAC (Idle Air Control) or "Air Bypass Valve", which is an electrically controlled air bypass metering unit, can be caused by either bad SIGNAL or one of a few types of crud interfering with the motor or other mechanical parts. Tar, corrosion, etc...

One good "STUFF" to put in electrical connections is plain old petroleum jelly also known as Vaseline. It does not interfere with electrical conduction, it protects the contacts from water, battery electrolyte, and other substances such as stray combustion gasses and oil vapor, and it also helps to lubricate the connector shell and contacts to make them easier to separate later on. It will NOT short out the contacts across to eachother however, so it's very useful. Use that after you have cleaned a set of contacts as good as you can, and it will protect them for a long time.

Used on BATTERY TERMINALS it will go a long way to preventing battery terminal corrosion that can eventually cause a battery to fail to charge up, and ultimately prevent a car from starting when it is very cold outside.

For the mechanical side of the house - any time I have a car that has sat for I don't know how long before I got it, SEAFOAM is indicated, but my old (and GOLD) standard has always been to run Berrymans B-12 liquid through the tank at double the recommended strength as a first clean out, and then occasionally at the recommended strength as a maintenance charge. I've seen B-12 do miracles before, you would want to swap out the fuel filter after the first time because it cleans out so much stuff!

But both B-12 and SEAFOAM will remove "Old Fuel Tar" very DEFINITELY, these two products are "NO SHIT" products that do what they claim, otherwise I would not mention them.

A detailed mechanical once over of the IAC is a good idea, look for corrosion or anything that might bind the mechanism. WD-40 is a good thing to use because it is not known to be destructive of electro-mechanical devices. Steer clear of Brake-Kleen, Starting Fluid, and those kinds of things because they have been known to damage electric components. BrakeKleen will in fact melt plastic, and cause the residue to flow where you don't want it. You can completely ruin an electrical connector with it.

Under no circumstances soak the IAC in a can of any kind of cleaning fluid, trapped cleaner inside a module like that can wreck it for good and all and if you ruin the electric motor in it you'll have to junk it and get a new one

[HillbillyScientist]

I have similar issues, but they're very inconsistent.