My 2002 I35 has developed a new issue. When you are stopped with it in drive, the engine starts stumbling...rpms are dropping down into the 600's. It is worse when you turn the air conditioning on. I am not sure what is causing this problem. Do you think it is the belt slipping?
Here is a picture of the engine rpm trend that I took. The trend starts off with the A/C off and you can see when the A/C turns on and how the engine stumbles become more frequent.
http://flic.kr/p/f47Lkx
Thanks in advance.
Engine Stumble
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joneill1975
- Posts: 18
- Joined: Wed Jul 02, 2008 5:52 pm
Re: Engine Stumble
I have added a video on youtube. You can see the engine stumbling at 0:30, 0:37, 0:49, 1:07, 1:20, 1:30, 1:37 and 1:44. You can really see the problem at 1:37 and 1:44.
http://www.youtube.com/watch?v=RLWiffAXvQg
http://www.youtube.com/watch?v=RLWiffAXvQg
Re: Engine Stumble
I've seen I30s stumble and sometimes stall at stoplights when the Mass Air Flow (MAF) sensor begins to fail.
Can you let us know the following information for a car with approximately 146,000 (from the video) miles:
1) Last time the fuel filter was changed?
2) Do you hear a buzzing noise (like a swarm of bees) in the back seat area of the car? If yes, this indicates a failing fuel pump.
3) Last time ALL O2 sensors were changed? Sometimes only one bad (e.g. throwing check engine codes) O2 sensor will be changed between 80,000 and 100,000 miles. The other sensors start losing their ability to adjust fuel mixture allowing the car to run richer than normal. Old O2 sensors with a failing MAF will result in poor mileage and performance that stumbles and bucks under load. Normally O2 sensors should be changed between 60,000 to 100,000 miles. If the original O2 sensors are running at 146,000 miles the sensors may not be throwing a code, but have lost sensitivity and will keep the car from delivering optimal power/economy performance.
4) Last time the car had a tune up (e.g. new spark plugs)?
5) Last time the car had the air filter changed?
6) Has the Mass Air Flow (MAF) been changed or cleaned (at maintenance interval) since the car was new?
7) Is the car currently or in the past used a K&N (oiled element) type air filter?
Can you let us know the following information for a car with approximately 146,000 (from the video) miles:
1) Last time the fuel filter was changed?
2) Do you hear a buzzing noise (like a swarm of bees) in the back seat area of the car? If yes, this indicates a failing fuel pump.
3) Last time ALL O2 sensors were changed? Sometimes only one bad (e.g. throwing check engine codes) O2 sensor will be changed between 80,000 and 100,000 miles. The other sensors start losing their ability to adjust fuel mixture allowing the car to run richer than normal. Old O2 sensors with a failing MAF will result in poor mileage and performance that stumbles and bucks under load. Normally O2 sensors should be changed between 60,000 to 100,000 miles. If the original O2 sensors are running at 146,000 miles the sensors may not be throwing a code, but have lost sensitivity and will keep the car from delivering optimal power/economy performance.
4) Last time the car had a tune up (e.g. new spark plugs)?
5) Last time the car had the air filter changed?
6) Has the Mass Air Flow (MAF) been changed or cleaned (at maintenance interval) since the car was new?
7) Is the car currently or in the past used a K&N (oiled element) type air filter?
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joneill1975
- Posts: 18
- Joined: Wed Jul 02, 2008 5:52 pm
Re: Engine Stumble
My responses are in red
1) Last time the fuel filter was changed?
I have not changed the fuel filter....when should it be replaced? 100k miles?
2) Do you hear a buzzing noise (like a swarm of bees) in the back seat area of the car? If yes, this indicates a failing fuel pump.
No, but the original fuel pump recently died and a new one was installed less than 2 months ago.
3) Last time ALL O2 sensors were changed?
The O2 sensors are original, but are not throwing codes
4) Last time the car had a tune up (e.g. new spark plugs)?
I replaced all of the spark plugs along with an ignition coil that failed within the last 6 months.
5) Last time the car had the air filter changed?
Air filter has been changed regularly, but I will need to check this one.
6) Has the Mass Air Flow (MAF) been changed or cleaned (at maintenance interval) since the car was new?
It has not been replaced, but cleaning it is a great suggestion....i will do that tomorrow.
7) Is the car currently or in the past used a K&N (oiled element) type air filter?
It has never had a K&N filter in it.
1) Last time the fuel filter was changed?
I have not changed the fuel filter....when should it be replaced? 100k miles?
2) Do you hear a buzzing noise (like a swarm of bees) in the back seat area of the car? If yes, this indicates a failing fuel pump.
No, but the original fuel pump recently died and a new one was installed less than 2 months ago.
3) Last time ALL O2 sensors were changed?
The O2 sensors are original, but are not throwing codes
4) Last time the car had a tune up (e.g. new spark plugs)?
I replaced all of the spark plugs along with an ignition coil that failed within the last 6 months.
5) Last time the car had the air filter changed?
Air filter has been changed regularly, but I will need to check this one.
6) Has the Mass Air Flow (MAF) been changed or cleaned (at maintenance interval) since the car was new?
It has not been replaced, but cleaning it is a great suggestion....i will do that tomorrow.
7) Is the car currently or in the past used a K&N (oiled element) type air filter?
It has never had a K&N filter in it.
Re: Engine Stumble
Thanks for the complete answers.
1) Cleaning the MAF may help. It won't hurt, Use spray MAF cleaner and follow directions. Do not touch the little wire element. I have seen many destroyed by Q-tips. Since you are willing to remove and clean the MAF, I would try to pick up a spare from a salvage yard, clean it, test it and keep it on hand for when you need it.
2) I usually replace the fuel filter every 20,000 miles. Usually at the same time I change the transmission fluid.
3) If it still has the original O2 sensors at 146,000 miles, while the may not be the direct cause of the stumbling, you might see an overall performance improvement with better mileage by changing them. Best maintenance practice recommends O2 sensors be changed from 60,000 to 100,000 miles. I recently changed the O2 sensors on my son's Maxima with the same mileage as your I35 and he noticed an immediate performance improvement with better mileage. One of his high-school friends brought his Honda Accord with similar mileage over last night and we changed the upstream sensor. He was really surprised at the difference it made after driving it last night. Last night he was telling his ricer buddies about the new performance enhancement that he chose (for now) over a cold air intake.
1) Cleaning the MAF may help. It won't hurt, Use spray MAF cleaner and follow directions. Do not touch the little wire element. I have seen many destroyed by Q-tips. Since you are willing to remove and clean the MAF, I would try to pick up a spare from a salvage yard, clean it, test it and keep it on hand for when you need it.
2) I usually replace the fuel filter every 20,000 miles. Usually at the same time I change the transmission fluid.
3) If it still has the original O2 sensors at 146,000 miles, while the may not be the direct cause of the stumbling, you might see an overall performance improvement with better mileage by changing them. Best maintenance practice recommends O2 sensors be changed from 60,000 to 100,000 miles. I recently changed the O2 sensors on my son's Maxima with the same mileage as your I35 and he noticed an immediate performance improvement with better mileage. One of his high-school friends brought his Honda Accord with similar mileage over last night and we changed the upstream sensor. He was really surprised at the difference it made after driving it last night. Last night he was telling his ricer buddies about the new performance enhancement that he chose (for now) over a cold air intake.
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joneill1975
- Posts: 18
- Joined: Wed Jul 02, 2008 5:52 pm
Re: Engine Stumble
So I cleaned the mass air flow sensor today and it did not resolve the issue, but I do have some more clarity to the issue. I now have a cylinder 3 misfire (P0303) code pending (no check engine light...just a pending code). Now I am thinking it may be the ignition coil on cylinder 3.
What are your thoughts?
What are your thoughts?
Re: Engine Stumble
I agree. That helps to pinpoint an issue to resolve. I've seen poeple move a failing coil to a different cycinder to verify the issue moved to a different cylinder as an extra confirmation step as new coils can be expensive.