Won’t start when colder than 25 degrees

[swathdiver]

Raising the BS flag. Our engines were designed to run just fine on 87 octane regular unleaded. Because 87 has 10% or so ethanol in it and 93 has zero in it then it will get slightly higher gas mileage but most likely not enough to warrant the extra cost per tank of 93 octane over 87 octane. We are talking maybe 20-30 miles more per tank. But it would still boil down to it would be cheaper to drive one mile with 87 vs. 93 octane.

The intake gaskets are most likely leaking in unmetered air into the intake stream. Gets harder to start the colder it gets outside and runs like crap until the engine warms up and gasket leak seals up enough to slow down the intake of unmetered air.

And you have the stereotypical symptoms of a long known problem of the intake gaskets leaking.

Around my parts 93 has 10% ethanol too. Even before the ethanol mandate, all automotive engines ran more efficiently with higher octane fuels. These engines are no different. If your driving habits are consistent, run your next two tanks on a top tier 93 and let us know the difference. In my parts the difference was recently less than .0015 cents per gallon in favor of 87, the prices have since fallen even more. I've run these tests on every car driven for any length of time for thirty years and the higher octane fuels have always been more efficient and beneficial to the engine.

Anyway, your intake manifold premise is worthy of merit and further inspection.

 

[02_Tahoe]

Raising the BS flag. Our engines were designed to run just fine on 87 octane regular unleaded. Because 87 has 10% or so ethanol in it and 93 has zero in it then it will get slightly higher gas mileage but most likely not enough to warrant the extra cost per tank of 93 octane over 87 octane. We are talking maybe 20-30 miles more per tank. But it would still boil down to it would be cheaper to drive one mile with 87 vs. 93 octane.

The intake gaskets are most likely leaking in unmetered air into the intake stream. Gets harder to start the colder it gets outside and runs like crap until the engine warms up and gasket leak seals up enough to slow down the intake of unmetered air.

And you have the stereotypical symptoms of a long known problem of the intake gaskets leaking.

You just perfectly described what my issues are. So I️ should replace the intake gaskets?

 

[rockola1971]

Around my parts 93 has 10% ethanol too. Even before the ethanol mandate, all automotive engines ran more efficiently with higher octane fuels. These engines are no different. If your driving habits are consistent, run your next two tanks on a top tier 93 and let us know the difference. In my parts the difference was recently less than .0015 cents per gallon in favor of 87, the prices have since fallen even more. I've run these tests on every car driven for any length of time for thirty years and the higher octane fuels have always been more efficient and beneficial to the engine.

Anyway, your intake manifold premise is worthy of merit and further inspection.

Octane rating has absolutely zero to due with efficiency of any engine and totally has everything to do with resistance to detonation (spark knock). You arent going to get a measurable amount of mileage increase using higher octane gas. Its throwing money away since it falls under the same argument of E85. It costs more to drive every mile using E85 or 93 octane than it does using 87 octane. Its simple math and simply facts. If you wish to pay more to drive then go for it. I like money and I like not giving away to people I dont even know let like.

 

[rockola1971]

You just perfectly described what my issues are. So I️ should replace the intake gaskets?

How long has it been doing it? Last winter? If so then I absolutely would throw a new set of gaskets on. If it just started then I would troubleshoot it. Spray some starting fluid or carb cleaner near intake/head mating surface and see if the idle increases. If it does then it just sucked in some of the spray in at your leaking gasket. Could also try to add 1/16-1/8 turn to intake manifold mounting bolts and see if it goes away too.

 

[02_Tahoe]

How long has it been doing it? Last winter? If so then I absolutely would throw a new set of gaskets on. If it just started then I would troubleshoot it. Spray some starting fluid or carb cleaner near intake/head mating surface and see if the idle increases. If it does then it just sucked in some of the spray in at your leaking gasket. Could also try to add 1/16-1/8 turn to intake manifold mounting bolts and see if it goes away too.

It did this last winter too, but last winter was my first winter with it so idk when it started, but the truck did sit for about a year without anyone driving it before I bought it.
I’m going to try the carb cleaner trick tomorrow and see what happens

 

[swathdiver]

Octane rating has absolutely zero to due with efficiency of any engine and totally has everything to do with resistance to detonation (spark knock). You arent going to get a measurable amount of mileage increase using higher octane gas. Its throwing money away since it falls under the same argument of E85. It costs more to drive every mile using E85 or 93 octane than it does using 87 octane. Its simple math and simply facts. If you wish to pay more to drive then go for it. I like money and I like not giving away to people I dont even know let like.

Nope, been doing what you say can't be done for thirty years. Do the math for me, 12.2 mpg @ $1.999 versus 13.2 mpg @ $3.139. Which one is less expensive per mile? In my earlier example I told you that 87 was cheaper by less than 1/10 of a penny per gallon to use at that time. ALL of my automobiles benefit greatly from using 93 compared with 87, many of them it's well over a 2 mpg difference. I reckon you've never run these tests which is why I suggested you try it.

 

[TwiztidPixel]

Before you tear the manifold off, start simple. Is the throttle body gross? Is the IACV working? Clean the MAF.

Is the CES light on?

Also, I agree that 93 fuel is not necessary.

 

[bassgas]

I have same issue except when it starts it runs fine only has 250th miles on it


Sent from my iPhone using Tapatalk

 

[02_Tahoe]

Before you tear the manifold off, start simple. Is the throttle body gross? Is the IACV working? Clean the MAF.

Is the CES light on?

Also, I agree that 93 fuel is not necessary.

CES light comes maybe once every 3 weeks but it’s a bad O2 sensor behind one of the cats. Maybe a dumb question but what does IACV stand for?

 

[02_Tahoe]

Nope, been doing what you say can't be done for thirty years. Do the math for me, 12.2 mpg @ $1.999 versus 13.2 mpg @ $3.139. Which one is less expensive per mile? In my earlier example I told you that 87 was cheaper by less than 1/10 of a penny per gallon to use at that time. ALL of my automobiles benefit greatly from using 93 compared with 87, many of them it's well over a 2 mpg difference. I reckon you've never run these tests which is why I suggested you try it.

Where the hell do you live? I want 1.99 a gallon