Engine Stumbles When It's Cold

[Twistiva]

Guys -

My Festiva is an 88L, 187,000 miles, original engine and transmission. No engine mods at all.

It runs great except when the weather turns cold outside.

It starts fine and idles fine (the idle gets stuck running high/fast when it's cold outside but I think that's a separate issue) but when the outside air temperature gets below about 45 degrees Fahrenheit, the car stumbles when I accelerate or even when I'm driving a constant speed down the road. You can feel the car stumble and sometimes even shake slightly. FYI, it even does this when the engine itself is good and warmed up, as in, driving for quite a while. The colder it is outside, the worse it stumbles.

I've had the loss of power get so bad that occasionally the car dies, but only if I've been driving for quite a while, ie, not just the 7 mile drive to work but after perhaps 30-40 minutes. When it dies it always starts immediately just fine and idles fine but if I step on the gas pedal the engine starts to instantly bog down and won't deliver any power. If I wait awhile (5-15 minutes) the engine will then run fine at a higher RPM/engine load and act as if nothing happened, until it does it again a little later. A couple of times when it has died, I was able to restart it immediately and goose/pump the gas pedal waaaaaay high on the RPMs, keep the engine running and get the problem to clear up within 3-5 minutes of revving the engine.

To summarize: stumbles even on a short drive, sometimes dies on a longer drive but both only happen when the outside air temperature is rather cold.

- Is it possible to get carberatour icing in a car????
- Are these 2 issues (the stumbling and occasional power loss/dying) related?
- Is this a vacuum problem?


Would greatly appreciate insight from a knowledgeable Festy mechanic. This is the only major engine/drivetrain problem I have on my Festy. I've owned Twistiva for 24 1/2 yrs and plan on keeping it for many more.

Thanks in advance!

[SiliconSoul]

Do you have a check engine light? If yes, get the codes and let us know what they are.

[eurotiva]

Festyboy (Arty) is very good with the carb cars, and dealing with cold climates. I'm sure he'll post something, just might be later when he gets off work.

[Twistiva]

Do you have a check engine light? If yes, get the codes and let us know what they are.

SiliconSoul - No, I do not ever get a "Check Engine" light. Sorry I didn't mention that earlier.

Festyboy (Arty) is very good with the carb cars, and dealing with cold climates. I'm sure he'll post something, just might be later when he gets off work.

eurotiva - OK, I anxiously await his reply.....it's been doing this for 2-3 years and every winter I just suffer through it since I don't typically drive my Festy on long trips, ie, it dies so rarely. Would be awesome to find the reason and get it fixed!

[FestYboy]

yes, you can be experiancing iceing at the venturies, but i'm thinking there's something else going on here... like possible coil breakdown in conjunction with other minor issues... a 25 year old coil has certianly given all it's worth by now. please note, that is NOT a diagnosis, but mearly a maintinance item to be addressed. then again, a weak coil kept Scrappt to a max of 62 mph untill changed. just thinking out loud here.

If you can, go to the carb bowl and remove the 2 14mm hex bolts a the bottom of the bowl and have a white rag under it to catch any debris that may fall out... i wouldn't be surprised if you saw crystal like substance come out.

gotta start somewhere...

[Twistiva]

yes, you can be experiancing iceing at the venturies, but i'm thinking there's something else going on here... like possible coil breakdown in conjunction with other minor issues... a 25 year old coil has certianly given all it's worth by now. please note, that is NOT a diagnosis, but mearly a maintinance item to be addressed. then again, a weak coil kept Scrappt to a max of 62 mph untill changed. just thinking out loud here.

If you can, go to the carb bowl and remove the 2 14mm hex bolts a the bottom of the bowl and have a white rag under it to catch any debris that may fall out... i wouldn't be surprised if you saw crystal like substance come out. gotta start somewhere...

Can a coil be affected by cold weather? (I apologize in advance if that's a stupid question.....I'll put it on my list to swap it out, boss.) And....what would the crystal-like substance be?

I appreciate your response. Like you said, you gotta start somewhere.

Hey, come to think of it, one last question for now....IF it is carb icing, what piece of hardware am I missing now/what has changed on my trusty steed from when it was a much newer car (i.e., when it did NOT do this) to now?, ie, what might have changed to possibly allow carb icing? When Festys rolled off the showroom floor in the northern reaches of Michigan, etc, they didn't experience carb icing. The Mazda engineers would have done something to prevent that from occuring.

[eurotiva]

Big difference in fuels over the last couple years versus twenty years ago. Not saying that's it, but ethanol is hurting older rubber parts