twinreds

The car is a 1986.5 5 speed with 110,000 miles, no mods except cats deleted. Timing belt and the usual stuff done within 3 years.
Last weekend I drove to a wedding, ran perfect. There was a light rainfall on it while she was parked but by the time I drove home was dry again, so for practical purposes, it did not get wet.
Drove it home from the wedding and no problems.
Two days later, I took it for a spin and I noticed that when shifting, the red warning would go off, almost as if it was stalling, but would go on as I released the clutch (I wonder if it was actually stalled and releasing the clutch under speed was restarting it).
Put it away and wait. Today I restarted it. I noticed that it used to idle around 800 rpm's, now is closer to 600. I burst revved it and it died. I restarted it and it died. I restarted it again and revved it upon starting and slowly released the revs until I reached 800 rpm's and it went again to the sloppy 600 range. This car was running perfectly a week ago. Is there something wrong or should I assume someone jealous poured something into my gas at the wedding?
Any help will be very welcome.

fiatrn

First, open the hood and check that the organ pipes are all still tight.

If so, check electrical things - cap, wires, battery grounds.

But check the organ pipes first. If one has come loose...

Petza914

Does it run normally once underway and it's only when you let off the gas when shifting or when it's stationary that it wants to die? If so, that sounds like a vacuum leak. Underway, the percentage of air sneaking in the right the leak is much smaller than when thers no load at lower RPMs, so the car will seem to drive fine when cruising or accelerating but want to die when returning to idle.

Also, by chance, we're you not using the ac when the car was running normally and the ac was on when you were having the issue?

Mrmerlin

Has the MAF ever been replaced? what does the gas mixture smell like?
check the MAF Ohms at the computer connector.
Also
Its possible the IAC unit has holes in the armature and the brushes are holding it,
(This unit is a wear item and may need to be replaced.)
NOTE you could also use a pick to move the armature and see if you can feel the armature being held by the brushes.
thus the engine wont idle the only way to verify this is to take the unit apart , by then its probably trash.

NOTE the new replacement part is made by Lowe no more Bosch parts are available,
this new part causes unstable idle to occur , Im not sure why,
maybe because its not built to the same standard as the original.

NOTE leaving the old unit in place could cause the computer drivers to get damaged,
thus damaging your engine computer idle circuit.
NOTE This idle circuit can be checked by bridging the two connectors at the test port on the top of the engine.
REF WSM for testing

Jerry Feather

Sounds like thrust bearing failure to me.
Edit: OOPS! 5-speed!!! But Still?????

Mrmerlin

Jerry on a 5 speed the only time the thrust bearing is loaded is when the clutch pedal is pushed to the floor,
NOTE the front side of the bearing takes the load,
compared to the rear side of the TB with an auto that has a preloaded flex plate.

NOTE another good reason to not press the clutch to the floor till after the engine is running,
as the crank will not have the benefit of oil pressure till the engine starts.

twinreds

Once running, it seems to correct, it would be for the first few shiftings, but it definitely dies and comes back when the clutch is lifted and the running transmission makes it restart.
I opened the Pandora's box (I mean, the hood). The organ pipes are tight. I hand revved from the engine and there is this initial swoosh that is very quick and short and not continuous. I never revved the engine from the engine bay, so I am not sure if it was therefore or not. From what I can hear, it seems to be coming from under the central organ pipe (the one that runs from one box to the other). I did check everything that I can see from above and I don't see anything that looks disconnected. Is that sound normal or do I have a leak? I thought that a leak would be continuous.

The Forgotten On

^^ If there is a crack in one of the ICV pipes a leak can get worse when the engine creates increased vacuum.

Happened on my 89, but it is easier to check on my 85, just take off one of the sides of the intake and have a look at the hoses.

Chances are if they are original, they're shot.

928NOOBIE

If you are going there take off the fuel rails and remove injectors and clean clean clean the bores, get some new O-rings..or if original, new injectors...4 hole vs 1...better atomization...they are consumable parts anyway. it isn't worth sending them off and having them rebuilt..you still have 36 year old injector technology..did I mention clean the bores? they will leak vacuum and are capable of leaking more than you could think. As me how I know..

if you haven't been under the intakes there is a lot of plumbing under there that will be oil soaked and cracked and the second you find and fix a vacuum leak more leaks will happen..then you'll find and fix the next one...and they'll tell 2 friends, and they'll tell 2 friends...and so on ...and so on...and so on...oh wait remember that commercial?...best to do an intake refresh and know everything under there is new.

No one puts in the kind of effort like we did in the past to sell women's undergarments...I think that's what its from..oh I'm drinking again....nice.