2014 Silverado recall - catch fire - bad gas mileage

xwinger · April 13, 2014

2014 Silverado recall catch fire - bad gas mileage

Anyone take their 2014 Silverado 1500 in for the recall about may catch fire? I had a sparkplug coil fall off because of corrosion. So took my truck in to have it fixed and at the same time they did the recall. Afterward I see that my truck is getting around 4 miles per gallon less. I’m getting about 17/18 highway and 13/14 city. At that rate I should just bought the ford & I could have gotten better with a Chyrsler. My 2012 Silverado never lost milage in just over 1 yr. My 2014 was only 3 months old and it lost 4 miles per gallon. I was getting 21/22 highway and 17 city. Not sure if it had something to do with the recall or sparkplug coil.

j13smiley · April 13, 2014

Hand calculated mileage or DIC calculated?

dan2014 · April 14, 2014

I too am experiencing the same decrease in mileage - the numbers are similar to yours. The DIC and my log book for fuel / mileage correlate very well.

The dealership states that there are no issues logged in the ECM, so they cannot do anything.

donaldusmc2003 · April 14, 2014

Winger

I also noticed the same thing after the recall. My mileage dropped about 4-5 mpg and my wire to the #6 spark plug also fell off due to corrosion with 2500 miles on the truck. The service tec told me he has never seen a spark plug wire come off.

fondupot · April 14, 2014

run a few tanks work before you attribute anything to the reprogram.

the mileage you're reporting could easily be from environmental factors, bad gas, driving style. etc.

Always hand calculate your mileage after each tank. Take the number of miles driven, divided by the number of gallons filled. In my experience the Driver information system is usually 0.5 - 1 mpg lower than the hand calculated average.

The recall reprogram did not effect anything on the truck regarding driving operations. Just they way it idles.

xwinger · April 14, 2014

donaldusmc2003 The exact thing I had and I believe the same sparkplug coil. That's not a coincident... Chevy dealer couldn't get the part and had to take it off a truck on the lot. So far not real happy with the 2014 at all. Loved my 2012.

fondupot I've done both DIC and by hand. Both show at least 3 to 4 mile per gallon drop. The difference in drive style is I've done more Highway driving the last couple months and city I've been trying to drive as concretive as possible. It still 3 to 4 miles per gallon off. I had a 2012 and it never dropped more then 1 gallon per mile the whole time I had it. In fact after about 1yr the city millage went up .5 to 1 mile per gallon. after 1 yr it was getting 17 to 18 miles per gallon in the city, from 16 -17. And Im taking it much easier on the 2014 which is suppose to be getting better millage!!

Also I put a least 15 tanks through the truck since then. Weather gotten warmer and still no increase. And from what I see posted here, others are having same issue...

chuckl1218 · April 14, 2014

After 3000 miles, I've tended not to baby her any more and mileage has not changed, even after the update for the recall - both DIC and manual calculation using the Gas Cubby app on iPhone. I agree with Fondupot on the difference.

Update: 85% city 15.5 - 15.8 consistently.

xwinger · April 14, 2014

chuckl1218 so whats your millage?

Im not saying its the re-programing but I'm not saying its not. I took it in for sparkplug coil issue and they did the recall service then too. And right after that I noticed the change. Could have something to do with the spark plug coil issue. Even the ride home after picking it up which is all highway I saw the difference. But figured I give a couple gas tanks to see. Well 4 months later its not improving. I was getting 21 - 23 on the highway and 16-18 city. Now I'm getting 17-18 highway and around 14 city.

This is not my first Silverado, I had a 2012

pm26 · April 14, 2014

chuckl1218 so whats your millage?

Im not saying its the re-programing but I'm not saying its not. I took it in for sparkplug coil issue and they did the recall service then too. And right after that I noticed the change. Could have something to do with the spark plug coil issue. Even the ride home after picking it up which is all highway I saw the difference. But figured I give a couple gas tanks to see. Well 4 months later its not improving. I was getting 21 - 23 on the highway and 16-18 city. Now I'm getting 17-18 highway and around 14 city.

This is not my first Silverado, I had a 2012

That's the same mileage my '06 crew cab Z71 4x4 gets with the 5.3 engine (non AFM) and 4 speed auto, 3.73 gears. It has been the same since new.

Which means that your truck with the AFM, and 6 speed automatic should get better gas mileage than mine or something is wrong.

juf · April 15, 2014

What symptoms did your truck have with that corrosion to the spark plug coil? My struck seems to bog down under acceleration a lot and I wonder if my truck could have a similar problem. How do I check?

donaldusmc2003 · April 15, 2014

I was sitting in it listening to the radio before work and it started to idle rough like it was miss firing. So i shut it off went inside and when i left started it up same rough idle and check engine light.

donaldusmc2003 · April 15, 2014

Juf

If your spark plug was foled out or the plug came off youd know it. Plus the check engine light would come on.

juf · April 15, 2014

Gotcha,

Thanks.

xwinger · May 5, 2014

juf - Iwas at the car wash just got done washing it and started it up and it was missing. A few minutes and the engine check light cam on. Next day I took it in.

For those interested, I was able to get to 18.1 mpg on the freeway by using cruise control at 60 miles per hour. But as of yet I have not been able to get back to 20 + like I was doing.

fondupot · May 5, 2014

juf - Iwas at the car wash just got done washing it and started it up and it was missing. A few minutes and the engine check light cam on. Next day I took it in.

For those interested, I was able to get to 18.1 mpg on the freeway by using cruise control at 60 miles per hour. But as of yet I have not been able to get back to 20 + like I was doing.

Where are you buying your gas from? Is it a top tier station like the ones listed at the link below:

http://www.toptiergas.com/retailers.html

Top Tier doesn't mean 93 octane. You can still use 87 and should use 87, just from a reliable gas station retailer. If you are using a mom and pop gas station around town, they could have bad gas.

I too had the spark plug issue that caused misfiring. I had my truck towed to the dealer with less than 3000 miles on it. They fixed the spark plugs AND the wires and added in dielectric grease between all the coil packs and the wire and the spark plug connections. I never saw a drop in mileage before, but it definitional has gone up since then. I just rolled over 7000 miles this morning and have been averaging 16-18 around town. And upwards of 20 on the highway usually going about 70 mph. Also for what its worth, I always use top tier gas from a reliable retailer. Usually its a Shell or Mobile station.

I would check your plug connections again.