Idle RPM fluctuation (slight)

[Melio]

When I'm driving I have totally normal engine operation, but when I shift into Neutral and let the engine idle.. the RPM fluctuates.. approximatly 50-100 rpms.. every second.

I'v never heard of this problem and Can't even fathom what it could be related to.

I thought maby it was fuel air mix.. running lean or something.. but I havent ajusted anything

I thought maby the throttle cable got loose, and it's not throttling the engine enough so it's mid stall mid run and the ECU is trying to maintain it.

Anyone got an idea? what should I check . .

92 talon, stock everything. (tsi, awd)

 

[IceDragon]

I have the same problem, alot of people have told me that they believe it is the air flow sensor starting to go... but I don't have money to replace that yet... so I can't try it, and I probably won't until it completely goes...

 

[Melio]

how much to replace it? can it be cleaned?

your talking about the MAF right?

 

[mac dre]

ive got the same problem too..also lookin for sum help

 

[ITSME4G63]

boot leak in the throttle body or intake manifold, woudl require you to replace the throttle body or intake manifodl gasket, your isc may be going or your tps may be going. I ha ve the same problem, But I know mine is due to the damned throttle body and intake manifold leaking. Need new gaskets y aknow

 

[Anubis_4_99]

i have sort of the same problem at the moment but it only happen's sometime's.. i can park my car, it'll die, then i'll start it up again and it'll idle perfect untill i get going, then i have to feather the gas while im stopped or it gets close to diein again.. anybody know what to check?

 

[sjgYFZ200]

Quick question, just want to make sure its not overlooked...are you venting your BOV?

Anyways, I did have this exact problem last year. The only thing that fixed it was replacing the headgasket, and right after that my ECU blew, so I cant be sure which one it was :thumbdown However check your BISS screw, make sure its still there...adjust if needed, and then go from there

 

[Anubis_4_99]

i just got the car like a week ago, so im not sure how to tell if he vented the bov or not.. but nothin's wrong with my gasket, and i cant afford to replace it right now anyway :thumbdown just spent $400 or more on drivetrain stuff.. it only started recently

 

[ITSME4G63]

i have sort of the same problem at the moment but it only happen's sometime's.. i can park my car, it'll die, then i'll start it up again and it'll idle perfect untill i get going, then i have to feather the gas while im stopped or it gets close to diein again.. anybody know what to check?

same problem I have, itll run fine, turn it off, start it , and sometimes itll just turn off right when u start it. Have to keep the rpms up via gas pedal. It has to be a boot leak. lissen to a hissign sound coming from your intake manifold or from your throttle body, if you have some time, replacing the tb gasket aint that hard anyways. but the intake manfifold is a bithc.

 

[Anubis_4_99]

i was thinkin boost leak too, but even when my intercooler was screwed and i ran without it the car didnt die.. (i only ran it long enough to get it to my buddy's garage like 30 feet away) i'll go thru it all tomorrow i guess.. any portland dsmer's wanna give me a hand?

 

[IronnFisTT]

I had the same problem.. turned out to be a flaky TPS connection. The harness was almost broken off, so i cut it off and replaced it with a female spade terminal.

-attia
94 Tsi AWD
98 Supra Turbo

 

[Melio]

So we got some concepts here.

head gasket damage : FIX Replace head gasket

blow off valve : Fix - replace BOV / check acuators

flaky TPS connection : Fix - replaced it with a female spade terminal.

Boost leak : Fix - replace the tb gasket

check your BISS screw, make sure its still there...adjust if needed


boot leak in the throttle body or intake manifold : Fix - replace the throttle body or intake manifodl gasket, your isc may be going or your tps may be going.


-

I don't know what a BISS Screw is
I have no idea where to find the throttle position sensor
I doubt it's the head gasket, but it's probably due anyhow.

it seems like it's a throttle position sensor. 135$ for a replacement

 

[ITSME4G63]

it seems like it's a throttle position sensor. 135$ for a replacement

just get one frtom a dsm at a junkyard

 

[sjgYFZ200]

is the hose that goes from your intake to your BOV not connected to the BOV?? that should be the first check...its real simple.

 

[Anubis_4_99]

if that's directed to me, then yes it is connected

 

[Anubis_4_99]

fixed mine, was a simple loose throttle bracket and the cable had alot of slack in it

 

[Melio]

I ajusted the B.I.S.S. Screw, it must have come loose.

car runs great. now if I can get the stinkin transmission out and have it rebuilt.