Mechanic Question

Hello –

I have a 2001 Chevy Silverado in which my check engine light came on. I brought it in for a dianostic hook-up and was there while they did it. The code was a mis-fire and running lean. They said the fuel cells were running high – around 17 and should be between 5 and 9? They said I need a new intake gasket which would cost around $325. However, on the way home the service engine soon light went off and they did not clear the code. So now I am thinking I should just drive it until it comes back on. If it is the intake gaskets are there any risks of driving it and not fixing it? The truck seems to start,run, and shift just fine. Wondering what your thoughts are?

Thanks in advance.

Chad

its only a chevy…lol..just kidding..

Run it the way it is. Mine has been on maybe 4 years now. That little light is not very high on the list of things that need to be fixed on my old silverado.

My 2001 Pontiac had the same problem at about 90,000 miles. (computer read out misfire and lean). I changed plugs and wires, cured the problem.I also had a couple wires where the ends were corroded in the coil pack.

If the CEL comes on,but does not flash I would leave it.I get similar codes on a Ford Contour.With 300,000 miles on it,still runs good.It has been doing that for quite awhile.

Have you noticed a loss in performance?

I could be an oxygen sensor also… that can come and go. An intake gasket is not electrical and if it is bad, it should always be bad ??? I lean (no pun intended) toward an oxygen sensor (that is not $325)

Could a person spray a little (etheir) around the intake and see if engine idle go’s up? Then you could see if you do have a leak.

does this happen after running for a while? does your truck have issues starting sometimes aftger warmed up already? do you smell a little gas after shutting off and such?

I would get it fixed. If there is coolant getting into the combustion chamber it will burn out the 02 sensor and also continue to get worse.

An 01 Chevy? You didnt list mileage. If high its practically normal for that light to come on. If its running good you can always put a piece of black electical tape over the light so you can’t see it….

If low miles I would tend to take it more serious and get a second opinion then balance cost of repair to how long you plan to keep it.

It could be intake gaskets. Alot of the time they will run poor cold and when the engine warms they will seal. If you have access to a scan tool start it and spray brake cleaner where the intake meets the cylinder head and watch the st fuel trim. It should drop temporarily if they are leaking. It could also be a o2 sensor. If that is the case you will most likely see misfires accumulate on one bank and the o2 mv will not be cycling responsively. Alot of the time I see the mv drop to zero. If the Intake gaskets are the problem there will be random misfires on all 8 cylinders.

I could simply be a fuel supply issue. I had lean codes on my ’02 F-150 and it went away after a Lucas brand fuel system cleaner treatment. I don’t normally put much stock in that sort of thing, but the mechanic recommended it and I’m glad he did — the code never came back.

Also, one thing to remember that the CEL won’t go dark right away when the problem is fixed. Once it’s on it will stay on for a certain amount of time. That can make an intermittent problem seem like a bigger deal than it is. Lean fuel is about the best code you could get — my understanding is that the worst case scenario is a bad idle or a loss of power. If either becomes noticable, then you take it in for a repair. Probably no reason to throw parts and $ at it in this case until you notice the symptoms.

Loomis is all over this….it is the intake. Cant be running that great with miss fires and fuel mileage is suffering. If it was an o2 sensor it should have a code for something like low voltage or insufficient switching for that 02 sensor. Get it fixed it will only get worse specially the colder it gets…

pulling the spark plug on the cylinder that had the missfire is your first tell-tale of what is going on. If you are getting leakage of coolant into the cylinder, the plug will tell you.

Otherwise, my check engine light came on at 110k. Said my O2 sensors were bad……..at 250k miles, the check engine light eventually burned out.

At 270,000 miles, I have “check engine”, service 4wd, abs break light…….can’t think of anything else………..she still purrs down the road, getting the same 16.5mpg that she got at 110k miles.
And that is after 10-12k mile oil changes on dino oil.

Gotta love the 350!

This sounds verbatim to what my 98 GMC Sierra did when my left bank gasket went. This was a caused by a terrible gasket design by GM. I’m not sure if they fixed that issue by the 2001 model year, but there is an aftermarket gasket that is a vast improvement in performance (I don’t mean like racing stripes adding 30 hp to a cavalier ). If my memory serves me correctly, it is a Felpro brand gasket. It has a metal layer added for extra durability. It is doable yourself with a lil patience and having proper torque information. The cost of the repair is mostly labor if you bring it in. All depends on your mechanics knowledge/comfort. Letting it go too long can cause engine corrosion, total gasket failure…which means coolant everywhere, engine overheating, and you stuck on the side of the road in freezing temps looking at a big green/pink puddle.