[bizzleb109]

Hi I recently changed the plugs and coils on my 2007 335i after the change the car drove fine for about 2 days then on cold startup it started idling real rough engine light flashes and half engine light displayed. I thought it might be my injectors called my mechanic I had purchased the spark plugs from eurocar parts the mechanic said it's probably the plugs he told me to buy new ones from dealer. If it was the plugs would it drive fine then after a day or so would it effect the idle if poor quality should I buy plugs from delaers?

[wilbur_the_goose]

Doubt it's an injector issue - you would've seen the problem before the spark plug change.

Did you carefully gap the plugs?

[bizzleb109]

He checked one-off them didn't check the rest I got them from euro car parts I would have thought they were gapped already. Any how if they were incorrectly gapped wouldn't I have noticed the bad idle as soon as I started the car after replacing plugs and coil?

[e90 John]

Do you have a scan tool? If you can figure which cylinder(s) are misfiring and switch the plugs and or coilpacks and the misfire travels with it, you can narrow it down to the plug or coilpack.

[dannyjones]

Double check the plugs, gap and torque. And check your coils are fully seated and connected. It's probably something simple

[bloppitybloop]

Originally Posted by dannyjones

Double check the plugs, gap and torque. And check your coils are fully seated and connected. It's probably something simple

Yea, this. It could be a coil that wasn't fully connected.

[robthewrench]

Most likely either a bad plug or a poor connection on either coils or plugs. The process is the same, pull your plugs again and check the gaps (or replace the plugs as well). Check the connections to the coils while doing this.

[AllBlackBimmer]

What plugs are you using?

Others have reported issues using non-"BMW" plugs... AKA bosch plugs...

You could put your old plugs back in and test to see. If your old plugs cause no issues, then you know your new plugs are whats causing the problem.

[XM_Rocks]

Originally Posted by bizzleb109

Hi I recently changed the plugs and coils on my 2007 335i after the change the car drove fine for about 2 days then on cold startup it started idling real rough engine light flashes and half engine light displayed. I thought it might be my injectors called my mechanic I had purchased the spark plugs from eurocar parts the mechanic said it's probably the plugs he told me to buy new ones from dealer. If it was the plugs would it drive fine then after a day or so would it effect the idle if poor quality should I buy plugs from delaers?

What part # did you get from eurocar parts?

Ignore the mechanic. They love to say buy OEM to get you to call the dealer and get scared on the pricing. Then they will buy the same OEM equivalent parts from their wholesale distributor for pennies on the dollar and charge you near the BMW OEM price.

Its the typical abusive relationship mind games that keep people coming back to them.

I am guessing like other have said its probably a coil not seated or a failing coil pack.

Originally Posted by wilbur_the_goose

Did you carefully gap the plugs?

The plugs should come "pre-gapped".

IIRC they have three prongs which would be impossible to gap anyway.

One of my most vivid teen memories is doing a spark plug change in my 1986 Fiero. Legs in the trunk, leaning over the engine and cussing/swearing trying to get the plugs out of the back bank of the V6 towards the firewall.

I also had to use that stupid spark plug gap tool/wheel.

So unless this is Marty McFly he shouldn't be gapping these, since we aren't in the early 90's.

[robthewrench]

As others have posted, you can't gap these plugs, but that doesn't mean you shouldn't check the gap. You can't fix one of these plugs, if the gap is wrong, but you should replace it. Just having the plug fall out of the socket and land on the electrode is enough of an impact to change the gap.

[XM_Rocks]

Originally Posted by robthewrench

As others have posted, you can't gap these plugs, but that doesn't mean you shouldn't check the gap. You can't fix one of these plugs, if the gap is wrong, but you should replace it. Just having the plug fall out of the socket and land on the electrode is enough of an impact to change the gap.

The only strange thing he claimed it ran fine for a few days aft the plug change then had issues.

Normally if the gap was changed, it was a bad plug or was some type of spark plug installation error I would think the plug would be ok.

I am going to lean towards a coilpack failure or came unseated.

[John 070]

Originally Posted by XM_Rocks

What part # did you get from eurocar parts?

Ignore the mechanic. They love to say buy OEM to get you to call the dealer and get scared on the pricing. Then they will buy the same OEM equivalent parts from their wholesale distributor for pennies on the dollar and charge you near the BMW OEM price.

Its the typical abusive relationship mind games that keep people coming back to them.

I am guessing like other have said its probably a coil not seated or a failing coil pack.



The plugs should come "pre-gapped".

IIRC they have three prongs which would be impossible to gap anyway.

One of my most vivid teen memories is doing a spark plug change in my 1986 Fiero. Legs in the trunk, leaning over the engine and cussing/swearing trying to get the plugs out of the back bank of the V6 towards the firewall.

I also had to use that stupid spark plug gap tool/wheel.

So unless this is Marty McFly he shouldn't be gapping these, since we aren't in the early 90's.

Yeah I was gonna say I used the green Bosch plugs equivalent to OEM, and I didn't gap them (my understanding was they came gapped)....

[Nitrousbird]

Originally Posted by XM_Rocks

The plugs should come "pre-gapped".

Originally Posted by robthewrench

As others have posted, you can't gap these plugs, but that doesn't mean you shouldn't check the gap.

Why does everyone assume he went with Bosch plugs?

My NGK plug all can be gapped (and needed to be gapped).

[bizzleb109]

Yes they are bosch plugs and coils.