Hey everyone! Been a long time reader, usually have been able to find my answers without asking until now.

I have a 2007 Volvo S40 2.4i, a little history on it, it has just shy of 200k miles, has a new transmission from a 30k donor, I recently replaced the transmission oil cooler, water pump, all the belts (3), tensioners, idler, pulley, cam seals, oil pump seals, coil packs (autozone), spark plugs (OEM), engine mounts, MAP sensor, and cleaned MAF sensor.

The car runs great up until it says try slow down or shift up and starts to barely accelerate, then will begin to violently shake until it is stopped and restarted. I can't pin point exactly what causes this as it is pretty random. From everything I have read this is usually solved with new coil packs or spark plugs but all of mine are brand new. When this happens the code thrown is P0300. I also have an EVAP code P043E.

I've attached some graphs of info I could grab, the yellow dot is exactly at the time the misfire and error message occured. Does anyone know if this could simply be a malfunctioning fuel pressure sensor? Does the EVAP code have anything to do with it? In the graph you'll notice some immediate fluctuations in readings when it happens, so I'm hoping someone on here can help me narrow down the problem, I've put a lot of work into this car recently and can't even enjoy it because it's scary as heck to drive anywhere haha



Thanks in advance.

 

OK - you replaced the coils - were they bad? Did you have a problem or you just thought you would replace them?

So - put the old coils back in and see what happens. ( if you were not having the "slow down or shift up " message before)

If you did not have the problem before - don't start guessing about sensor XX is bad. Use your codes and clues to develop a reasonable diagnostic process. A process that is not guess, replace, and wish you didn't buy that last part because it did not fix anything and you really could use that money to pay for other stuff.

 

I appreciate the response, yes was having the issue before and read that it was most likely the coils and/or spark plugs so just did them all. Hadn't been maintained very well from the previous owner so figured just do them all and not have to worry about it again for a while.

 

I'd MUCH rather have old Volvo coil packs than new off-brand coil packs. Those things cause SO many problems. Also, make absolutely certain that the plugs you put in were the right ones, and that they were properly gapped.

 

I used https://www.fcpeuro.com/products/vol...t-ngk-lfr6d5kt

Unfortunately the coil packs were the only parts I didn't replace myself so I do not have the original ones anymore. I don't know if AutoZone will let me return the duralast coils without box, may have to take a loss on that but really don't care if I can get this issue fixed. Would these be the correct coils to use? https://www.fcpeuro.com/products/vol...ch-kit-00082x5 or am I looking for Volvo stamped coils?

 

I think those coils from FCP Euro would be the best ones you could get. Also, don't discount the option of getting good used coils from eBay or a local boneyard, as these things generally outlast cockroaches. ;-)

If you do buy quality coils packs, make sure you're getting them from a trusted vendor, as there are a LOT of counterfeit parts floating around out there, and they're going to be nothing but heartache.

 

No luck finding the coils around my area. I did pull the packs and there is is bunch of dielectric grease in the boot im assuming from when they were installed before I did the spark plugs, enough that I see it at the top of the boot on the spring and was on the top of the new spark plugs when I removed it.

I'm not sure how to check the gap on this kind of plug, the box said pre gapped to 0.028, but does this look right?

 

Yeah, those are usually gapped per spec, since they don't have the little L-shaped ground anode to bend in transit. That "old school" plug was really (!) easy to mess up.