john89011

Alright, in the past week I noticed the car started running funny. During Idle, the car vibrates like it's about to stall. If I switch from D to N it improves things a little since the RPM slightly goes up. I don't have any CEL or warning lights on but decided to scan it anyways and now see

P0300 multiple/random missfire
P0304 Cylinder 4 Missfire

I don't know where to start? Car has close to 150K on the dash, replaced the wires and plugs less then 30K miles ago (the ones from letmotorsports)

I also have to replace the IC pump (again) not sure if that has anything to do with it.

Thanks!

c32used

Based off a similar issue I had the multiple / random misfire is usually caused by one cylinder misfiring...well my issue was cylinder 6 gap was off from rest...I bought new plugs and thanks to AMG JERRY got them installed and gapped properly and issue is no longer non existant. I would check that the gapping on all are identical also that the wires are making firm contact and lastly the coil packs make sure there is no currosion on them or underneath them if so clean all contacts properly. GL

Zeppelin

Make sure Cyl 4 plug wires are on tight. If they are I would swap the plug wires from Cyl 4 with another cylinder and then re-scan the codes after driving for awhile. See if the same cylinder is mis-firing or it moves to the cylinder you swapped the wires with.

///AMG4EVER

I recommend going back to OEM wires.

loungn14

+1

first thing to do...see if its wires or cold packs

john89011

Great! I'll give it a shot.. thanks for the input guys.. also would the alternator have anything to do with it? At night I can see the headlights slightly flickering but not always.

loungn14

Nope, and not the johnson either...

john89011

Back to this...

Today, about to go home from work I start the car and see "Battery/Alternator low, visit workshop!" flashing in red. I left the car in the parking lot since I was not sure if I would make it home before the car would stall. I am about to order the Valeo Alternator from alleuropeanautoparts for $290. Is this a DIY job? Has anyone replaced one before?

Btw, I did not swap the spark plugs yet posted in original threat, probably will replace them when I do the alternator.

///AMG4EVER

Check your idler pulleys.

You don't necessarily need to swap the alternator; a bearing in the pulley system might be busted.

Turn on the car and take a look at your belt. If you can get someone to rev the car while looking at it you might see some wobbling.

GL

TemjinX2

yeah i had a similar problem. it turned out to be the alternator after all. I got it installed for $140 at my shop. Its basically a 2hr job at shop. So probably 2-4hr diy. Its near the bottom of the engine. its not really hard, just a lot of work and kinda a pain in the ****.

john89011

I decided to do it myself and what a pain in the a**... any one ordered the Valeo Alternator and noticed the alternator pulley is not as wide as the OEM? I noticed it after I put everything back together... old pulley has 7 tracks and the new one has 6. Now I guess I'll have to take the old OEM pulley and put it on the new alternator.

TemjinX2

i didnt notice it since i had the shop put it in. But i've been driving it for over month..without any problems.

john89011

yea the belt sits on top of the outer raised thread, are you sure they did not swap your pulley?

SUPR C

You have to swap out the pulley. My mechanic did it for free. I installed it myself and it was a pain the a**.

john89011

yea i am having problems with the bottom portion of the Altenator... the bolt won't go in so I am guessing it's not aligned right. I don't want to take it out since it took me almost two hrs just trying to get it in between the sleeves. I hope I can remove/install the pulley without moving the altenator and have to figure out how to align the bottom since there is not much room to see what's going on. It all makes it more harder since I am doing it in a parking lot at work.. would be nice it if was sitting home in my driveway.

john89011

Swaped the alternator pulley (local car parts store did it for free in less then a min) then I put the alternator back in the car (this time it went a little easier, guess was lucky) and the car is back up and running.

I still have the vibrating issue, replaced two spark plugs at cylinder 4 and no difference (although the plugs looked pretty bad) I guess next step is to replace the wires (anyone know if LETMOTORSPORTS still sells them? I don't see them on their website) if that does not work, I'll go back to OEM I guess