2000 740IL - engine misses or hesitates from 15 to 35 or so on the way to 70mph.
did a complete tuneup including all filters, and especially gasoline filter.
Still acts like its hitting on 6 or 7 at low power on speeds.
Help!

2000 740IL - engine misses or hesitates from 15 to 35 or so on the way to 70mph.
did a complete tuneup including all filters, and especially gasoline filter.
Still acts like its hitting on 6 or 7 at low power on speeds.
Help!

Explain in more detail about your "complete" tune-up.

The problem sounds electrical -- plugs, or ignition coils, or both.

Does it do it all of the time, or does the problem go away after you've been driving for a few minutes?

Speed doesn't directly affect misfires as far as i know.

The problem sounds electrical -- plugs, or ignition coils, or both.


Ding.

I'm guessing oil seeped into the plug area and got into the coils.

Every time I accelerate and the rpm goes over 3000 I get a bunch of misfiring code but only on the right bank cyl, 7,5,8, sometimes six. I just changed the valve cover gaskets, spark plugs, fuel filter, also switched the ignitors around, also oxygen sensor codes some times, the car was running fine until I had to accelerate to pass an other car two weeks ago, any suggestions, I have all data, I have some mechanic experience,but not an expert,
Thanks for any help you could spare,,

Andre

Hi brubray here.
The tuneup consisted of 1 new Fuel Filter, 2 New Spark Plugs and 3 Induction cleaning
It was time for a tuneup and I really thought the fuel filter would stop the missing.
But obviously it didn't.
The code system works but no codes are being shown
The car has 190k miles and normally runs like a top. beautiful car well cared for.
I thought it might be the transmission, the mechanic, who I trust, says the transmission is fine. I thought it might be an oxygen sensor, he says no the sensor is fine.
Also checked the brakes. They were excellent.

re: the last question "does the problem go away after awhile"?
I thought so until this morning and after about 30 miles at highway speeds it happened again at stoplights on the way home.
(I don't think it hesitates after about 35 mph. It definitely does starting up from dead stop from about 15 to 30-35mph)
thanks for all your suggestions. keep them coming please

Hi brubray here.
The tuneup consisted of 1 new Fuel Filter, 2 New Spark Plugs and 3 Induction cleaning
It was time for a tuneup and I really thought the fuel filter would stop the missing.
But obviously it didn't.
The code system works but no codes are being shown
The car has 190k miles and normally runs like a top. beautiful car well cared for.
I thought it might be the transmission, the mechanic, who I trust, says the transmission is fine. I thought it might be an oxygen sensor, he says no the sensor is fine.
Also checked the brakes. They were excellent.

I'm assuming that you were using the numbers to bullet-point what you included, and that you didn't only change 2 spark plugs, but rather all 8.

Anyway, overdue fuel filters don't cause misfires, they cause slowness. And I still say you need to look at the electrical side of things, or maybe even air, but not fuel. And when I say air, I mean like a vacuum leak (very common).

It's insane that your check engine light isn't on when you're getting misfires. I wouldn't replace any sensor unless you at least got a code for it.

Do you notice any smoke, especially on startup?
What kind of spark plugs did you buy?

The plugs, all eight of them are NGK Platinum.

brubray here again
I appreciate all your comments. I am printing them out for my mechanic. I talked to him and he agrees to definitely check out the electrical and the air leak possibility.
Keep the comments coming. This is a great service.
brubray

Thank you All,,
My problem was a collapsed driver side Cat, Burned bad,
car runs fine now just still getting the O2 codes, can I remove the sensor?? can I use the just the plugs like some one posted earlier, and not to have the engine run rich??

Thanks Again

Thank you All,,
My problem was a collapsed driver side Cat, Burned bad,
car runs fine now just still getting the O2 codes, can I remove the sensor?? can I use the just the plugs like some one posted earlier, and not to have the engine run rich??

Thanks Again

EuropConvers, what do you mean -- "can I remove the sensor?? can I use the just the plugs like some one posted earlier, and not to have the engine run rich?"

And what happened to Brubray?

Someone wrote that he removed the rear sensors and just plugged some old ford spurk plugs into the rear O2 sensors and left them out side next to the exhaust, but I did not see if it worked or not??
Anyway my car is on the lift right now and I am measuring the CO level, see what happens,,

Someone wrote that he removed the rear sensors and just plugged some old ford spurk plugs into the rear O2 sensors and left them out side next to the exhaust, but I did not see if it worked or not??

http://www.bestdesignever.com/osv/halfbaked.jpg

I appreciate every bit of information, the reason we are here at this board to learn more about our cars, with out spending lots of money on dishonest mechanics, so please keep it professional, if it is with in reach.

Best Regards,,

Thanks guys. And a special thanks to Plik who suggested ".....And I still say you need to look at the electrical side of things, or maybe even air, but not fuel."
He was dead on. We, Johnny Ha, my mechanic, started with the cheapest thing to look at the "air". He replaced all the hoses that had anything to do with fuel and oxygen transport.
Voila! This engine purrs like the proverbial Swiss Watch, and, it cost the least of all the efforts we thought left.
Thanks Plik. You get the Big Green Light for this one.
brubray

Thanks guys. And a special thanks to Plik who suggested ".....And I still say you need to look at the electrical side of things, or maybe even air, but not fuel."
He was dead on. We, Johnny Ha, my mechanic, started with the cheapest thing to look at the "air". He replaced all the hoses that had anything to do with fuel and oxygen transport.
Voila! This engine purrs like the proverbial Swiss Watch, and, it cost the least of all the efforts we thought left.
Thanks Plik. You get the Big Green Light for this one.
brubray

Brubray, I'm so glad to hear it. :)

Let us know if you ever need help again with anything, we're all here for ya brother.

sorry to say, the hesitation is still on my 2000 740IL when increasing speed from the 25 through about the 35 mile range. It feels a little like the engine has just injested a little water or something then as the speed goes on it goes away.
I have changed NGK Platinum plugs, new fuel filter, oil filter, air filter(s). Mibil 1 Oil change, new air hoses, cleanup for valves.
Plik said he thinks it is more likely air or electircal. Where do I start with elecrical?
brubray

Not sure if Mines tdoing the same. I have a 2001 740Il that skips/surges at 1500-2000 rpm thought it might have been fuel or o2 sensors also. Took it in to the dealer today. Fault code showed transmission, they said it was dropping in and out of overdrive. Also charged me $200 to reprogram the elctronics on the tranny. That didn't make a difference. I have had no noticeable slippage or problems at speed.

Hi,

I have the same problem with my 740 I 2000 I need to change the tensioner and adjust timing chain. Even if I have to buy all tools I still will be 5 times cheaper than a service from Utah…..PLEASE HELP!

To brubray....I have a 99 740i Sport that originally started to seem like it was skipping/surging or going in and out of drive for a few seconds and I was told (By the dealer) that it was the transmission computer, but I also had intermittant DSC and anti-lock lights coming on, and after they stayed on it would stop surging. The DSC and anti-lock are now on seconds after starting the car and after reading some posts I found out that this could be the speed sensors. It no longer surges or goes in-out of drive intermittantly after the DSC and anti-lock light have been consistantly on. I don't know if the speed sensors could be causing your problem or not, but if you have exahsted all other efforts it could be something to check out. I had spinal surgery so I havn't gotten around to changing my speed sensors yet, but I have a feeling those lights are going to go out after I do.

Now I have an internittant mileage problem, I was getting 14-18 mpg city then it just dropped down to 6 mpg,This happened a few times before, I am thinking it is the OSV. If I place my finger underneath the OSV and cover that little vent, it makes a weird humming noise but doesn't change the RPM. Anyone know if it is supposed to make that noise?