Elantra XD (2001-06) :: Sudden Drop In Mileage And Hard Shifting
Aug 24, 2013
All of a sudden my fuel consumption dropped from 28mpg as read from the computer display in the dash, to 21mpg. This was not a gradual drop, it was at 28mpg one day and 21mpg the next day. There is no service light on, do these cars produce codes that don't trigger the service light?
A few months ago the vehicle was getting stuck in various gears and lunging, this was from battery corrosion dripping down and eating away at the transaxle range sensor. I cleaned up the battery and replaced the range sensor and the vehicle was driveable again. It re-learned the shift timing and seemed to be ok, then about a month ago it seemed to be forgetting the learned shift positions after sitting over night, I replaced the battery, thinking it was in a marginal state where it would forget the program while sitting. The shifting is still hard sometimes but this seems to have worked but, now my mileage is horrible.
I thought I'd just change out the oxygen and air flow sensors but, then looked at how much they cost now, and realized this would be some costly trial and error. Is there a methodical way to troubleshoot this issue, any way to pull the sensors and measure them?
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Why all of a sudden the mileage indicator on my 2012 suddenly dropped about 5 miles/gallon, both highway and around town? The car has only 9000 miles on it. Has there been a service bulletin regarding the "Eco'" mode? Having the "Eco" mode on or off doesn't seem to make a difference.
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My 03 (129k miles, 2.7 AWD) is up to date on all maint (this summer saw new timing belt etc., transmission service) and oil is current. Spark plugs are due at 131k. Air filter is new, tire pressure maintained at 30-32psi.
MPG has consistently been ~20, slightly more on trips. October 27 to November 26 was 19.8 mpg. Putting on brand new snows (General Altimax Arctic) knocked it down to 17.5 mpg for the next ~250 miles. However, since early December it's dropped again to 13 mpg!
Mechanic just checked for brake drag (none - rotating one wheel turns all 3 others easily); no pulling, rolls well in Neutral. No engine symptoms (missing, bucking) or CEL lights. Power seems a little diminished (for instance, it takes longer to shift during acceleration sequence).
I will add my Lucas Oil gas treatment just in case it may be injectors. My mechanic says he has seen MPG suffer from certain gas brands (and I do wonder if the tank fillup after which the MPG dropped had something to do with it).
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I have an 08 2.0T and it just suddenly had a huge drop in gas mileage. I recently had new tires put on and an oil change (about 35k miles). getting closer to 40k miles now and wondering what could be causing this. Usually I get about 30-33 mpg easy on the highway. Now I'm getting 24-26 mpg. Already checked the tire pressures. they're to spec. no gas leaks from what i can see.
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I commuted to LA 2-3x a week. The mileage on my car is now at 90k. I have had an average of 40 mpg since new, but suddenly it began to drop. We took it to our local Toyota dealer and was told it was most likely a cable that needed to be cleaned. That was $160. It didn't work.
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I was driving up a hill today at about 30 mph with .9 miles remaining showing on my EV battery meter when all of a sudden it drops to 0 EV miles remaining and shows only 2 of the battery level bars (which is very very low), and the engine of course turns on. What happened?
I promise I did not push the EV power bar over its threshold. I monitor that like a hawk. I also know for a fact that it jumped from .9 to 0, because I watch that part like a hawk. This part of the trip is near the end of my drive home and I've done it about 50 times so far with no issues. With .9 miles left at that point on the hill I have always been able to make it to my driveway with .4 or .5 remaining, so this is very odd.
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I have a 2004 Subaru Forrester with a 2.5L engine (non-turbo) and about 137,000 miles. I usually get just a bit more than 300 miles on a tank of gas. About 3 weeks ago, I took the car for a major tune up (and they also replaced a valve cover around the spark plugs area). After the tune up, the car was running great and I was still getting about 300 miles to the tank. Within the last 10 days, I noticed that the gas mileage on the car has decreased - I am now getting closer to 250 miles per tank. The mechanic rechecked the fuel lines and test drove the car two days ago but did not see any signs of leaks. The weather was near freezing for about a week but has warmed up again to the 40's. My driving habits have not changed and I am driving the car the same way as before. I am stumped as to why the gas mileage would drop that much. What might be happening?
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I am using a 2012 Prius and I was running around 23KMpL average. For sometime I am seeing my mileage around 17 - 18 KMpL. What could be the reasons for this ?
The only change happened in between is that I had a accident which I had to replace the front buffer.
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My '05 Prius has been going strong with just passing the 200k mark recently. However about 2-3 weeks ago after I replaced the PCV valve, I started getting really bad gas mileage. I'm talking about getting an average of 45 mpg in city/highway combo down to 30 mpg. Filled up my tank twice from empty so I'm pretty sure it's not just bad gas. Highway driving does slightly better than city.
Today I noticed that my acceleration from stop is just absolutely terrible. The car responds really slow and sluggish and takes a while for it to realize I want to go. Low speed doesn't get good mileage at all. It seems I get normal mileage at almost 65 mph, not sure why.
I don't think the 100 degree weather we are having here in Texas is causing THAT much of an effect because last year and two years ago during 100 degrees, gas mileage was normal. What to check? I searched and most talk about cold weather. I have a relatively new 12V gel battery so I doubt it is that but I can try disconnecting it.
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I am trying to fix the pesky hard start that I have. My car doesn't start right up anymore unless it is frozen cold. Other than that it takes 2-3 cranks sometimes 4 to turn over. That's annoying and embarrassing and I am trying to remedy it ASAP.
I have a check valve and Purge valve on hand right now. In my research it seems this is where I need to focus. I do have an engine code it was P0456 this time. I also have a gas cap.
I have a check valve because of the all too familiar cutting off early at fuel pump problem. I wanted to start there first since I am sure something needs repairing down by the fuel tank and since the problem is common. And hopefully the valve will work with the fill up and MAYBE with the start, if not that is where the purge valve comes in.
I got as far as get the 2 12mm bolts off and then couldn't make it any further.
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I have had the Santa Fe back and forth to the garage no power. We where driving it and all a sudden dropped power can't rev motor over 3000 rpm. Garage said they fixed it with dry gas and more gasoline b/c it was "low" between 1/4 and empty?
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I bought a new 2013 Hyundai Elantra Coupe this past August and this is my first car.
My first concern was that Hyundai advertises 27mpg in city and around 37(?) for highway. I acknowledge the fact that Hyundai recently had to lower their mpg estimates for some of their cars and provide reimbursements but however, these reimbursements are for 1-2mpg difference. My car after more than 6 months is still only getting about 14-15 miles on a casual drive in the city and only about 19-20mpg combined and about 24-25 on the highway! I am only getting about half the estimate for in city! I do not drive aggressively. In fact I am a pretty safe driver since I am a new driver and cautious about everything. I am also using premium gas on my car. I called the dealership I got the car from and they were trying to tell me about the reimbursement program which I already knew of... The reimbursement based of the 1-2 mileage difference is not what I want. I want to fix it and get close to the estimated mileage as I can. What is the best way to go about doing this?
The other issue is that sometimes when I hard brake, my car makes a loud grinding noise. My dealership's service center said they could take a look at this. I was mainly wondering if there is anything I should be concerned about for this?
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I have an '04 Elantra GLS with 274k on it. I've been caring for it myself with basic maintenance; that said, I changed the oil in it about 100 miles ago. Halfway through my drive home it started to idle rough under 1k rpm.
I've noticed a lot of other Hyundai's have the same issue. What would be/is the most COMMON cause of this? Timing belt? Basic tune up? I moved a state away from my local shop and I refuse to go to a Midas/Jiffy/ect.
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Driving in sunny so cal yesterday never a problem with the car just an oxygen sensor- I was cruising along at 75 and all of a sudden the oil light comes on - immediate loss of power and i pull over to the side of the road and shut it down. try to restart and it just clicks.....tugged on the crank through the wheel well and it will not budge...oil is ok and plugs were pulled and they seem fine....oil pump...fuel pump....starter hopefully something simple and inexpensive I hope.....what is the difficulty in changing out the starter and could this be the issue?
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I recently had my oil changed. And when I was driving home noticed my clock had reset. I have a brand new battery. I set the clock back to the right time, then headed out of town the next day. When I went to turn off the interstate my blinker did not work at all. When I pulled into a station I saw neither one worked.
My 2006 Elantra is also suddenly using double the amount of gas. I took it to a place 2 days later when I got home. The turn signals decided to start working the second it went in the shop, yet hadn't worked 10 minutes before I got there, and they didn't know what the cause of the clock resetting itself would be, or the higher gas usage.
I did have somebody check to make sure my battery cables were tight. I am at a loss yet these problems all started at the exact same time. What I could have checked? My car ran great before this last oil change. Now I don't even go out of town because of it hogging gas.
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I have a 2003 Elantra, which I've had for several years, and love greatly. Recently though, she's been giving me problems.
When it first started happening, about 6 months ago, it seemed that she was simply sluggish, and wouldn't accelerate as well as normal when I pushed the gas.
It has gotten worse from there, within the past 4 months, sometimes when I turn her on, she idles very rough, and the entire car shakes. Originally when this started happening, if I turned her off and back on, she would run smoothly again. Unfortunately that's no longer the case.
If I attempt to drive anywhere when she's acting up, pushing the gas makes the RPM drop down, and she doesn't move. This has caused a lot of problems at stop where I'm turning onto a busy road. Occasionally when I'm driving around, her RPM drops far below what it should. For example, she frequently drops down to 700 RPM when I'm driving 35 mph... normally when going that speed, the RPM is about 2000.
Most troubling to me is the fact that the engine turns off on me without warning sometimes. I've had her do it when I'm at a stop waiting to turn, at stop lights, and dangerously, even when I'm slowing down through traffic or getting ready to pull into a parking spot.
I've tried multiple things, fuel injector cleaners, replacing temperature sensors, and I've checked all the valves, wires, and hoses. I've had it attached to a code reader and of course she never acts up while it's attached.
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Can't run a/c rpms drop to almost 200 from 1200-1500rpms. Really bad when at at traffic light. I have to constantly press gas pedal.
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My nephew's car is a 2002 Hyundai Elantra GLS manual. His RPM's hang when he shifts and it is a pain to shift.
I took it to the dealer and had them do TSB#04-36-011 Delayed RPM drop between shifts. This TSB supersedes TSB 01-36-025. Here is a link for the newest TSB : [URL] ....
The TSB Basically tells them to erase ECM adaption values. Then, you update the ECM with new FUEL cut-off logic. When we drove off the dealers lot the delay was not better, just different.
After driving it for a day or two we saw improvement. Now when you push in the clutch the RPM's go up slightly for a second to burn off the gas then the RPM's drop faster than before.
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My '03 Elantra has started making a screeching sound when I drive it. At first, I thought it was due to the cold weather, but it has occurred even on warmer days. It makes the noise intermittently, sometimes not at all. Sometimes when I turn sharply or back up, or when I just drive it. What is odd is that I had the belt changed last spring, and I inspected it and it does not seem ripped or stressed at all.
Not sure if this is related, but I noticed that my gas mileage has been greatly reduced. Last week I filled up a full tank and drove about 6 miles. When I filled up, the needle was above F. Later when I got home, the needle was just a few ticks below full. Within two days, I was at half, only driving a combined total of about 16 or so miles, city driving. This car has always had great gas mileage, even with snow tires. My mileage is 56,815, and I've checked for gas leaks and found none. My RPM's don't rise, my engine does not overheat, though I did find some weird oil on the black hood on the engine last week when I checked the belt. I checked the oil levels and they were good.
I'm taking this in tomorrow, and am scared that this is the end of this car. What may be the cause of the screeching and loss of fuel efficiency?
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I've read a lot on here that people have issues with their elentra when shifting gears, I have been having this issue for a while now and have been trying to trouble shoot the issue. (some make the mistake of using GL5 instead of GL4 or the master, slave cylinder are bad.
I've checked all of those symptoms and all is still well oh and my car is an 07 with 141k miles on it with the clutch replaced at 75k miles on it.) I went to a thicker gear oil from 75/85 to 75/90 which isn't much of a difference. It did work for a short time with the rough shifting gears but it's doing it again.
From 1st to 2nd (especially from initial start then after it warms up it's not as rough but still grinds and 3rd gear is on its way to grinding) I've started with all the small things and i'm considering rebuilding the transmissions synchronizes in the the input and output shafts for the gears.
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06 Elantra Limited, 96,xxx miles. When I'm idling at a light or something, the Rpms drop for a split second, almost to the point of stalling, but recovers. Happens in a split second. Does the same thing even when driving, but does it more frequently when idling. It even does that when I first put my foot on the throttle to accelerate from a red light.
I've cleaned the throttle body but it still does it. I've taken it to 3auto parts stores. One said that battery was bad. The other said the battery is fine but alternator is producing low. The last said both are fine.
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