uphoto

This beautiful morning I got in our 957 and when it was warming up I noticed it had a little hesitation when giving it any gas but seemed fine once it was warmed up. While on the freeway I got a flashing CEL and the car starting shaking a bit. Not much response to the gas pedal and it shakes even more when giving it gas.

I pulled over and turned it off and back on. The light went out but after a few hundred yards the CEL came on solid and then after a few more moments back to flashing and shaking.

I changed the coils as a preventative measure about 6k miles ago (at 88k miles right now), could it be one of those went bad?

Anything else it could be or I should check?

Appreciate the help.

Shawn Stanford

It definitely sounds like a misfiring coil. They do go bad sometimes. Pull the codes and see if you're misfiring on any particular cylinder. If you are, then swap the coil with another cylinder (check the business end of the misfiring coil to see if it looks burnt or crusty), and see if the misfire follows.

If it's smooth at idle and rough on throttle, you might want to consider fuel pumps. The check for that is to pull the fuse for the left side pump (14 or 15, I think), and see if it dies.

uphoto

Thank you Shawn, appreciate it. All fuel pumps were replaced about 20k miles ago but I'm going to check coils first.

uphoto

Ran a scan and these are what came up.

P1248 Basic boost pressure adaption - Above upper limit value *not sure what this is, both valves have been replaced.
P0301 Misfire, Cylinder 1
1503 Additional brake light *I get a random check brake lights, I think my 3rd brake light is dying.

So looks like cylinder 1 might have a bad coil. When I get a chance I'll pull it and check it out.

tpwierimaa

How many miles are on the car? at 63k I have found most of the coils and plugs going on my 08 GTS. I am replacing them all as they have started failing literally one every few weeks.

I understand that coils and plugs start going around 60k, but I am no expert.

uphoto

Mine lasted 80k+ miles with really no issues, I replaced all of them when doing the plugs. Was surprised to see one of the new ones fail but it has a lifetime warranty on it so a new one will be ordered soon.

Shawn Stanford

If you saved the old coils, swap one into cylinder 1 and see what happens.

uphoto

Took the coil out of cyl 1 and swapped it with coil in cyl 3 and still had the same code come up!

Went to check the plug thinking that it's the problem and because the engine was warm I couldn't get the damn plug boot out of there.........it started to come apart as I tried to use some plyers to get it out. Decided to let it sit overnight to see if that makes it easier to pull that damn boot out of there.

jtakhtalian

A little bit of dielectric grease at the tip of the coil should solve the sticking problem down the road. It'll prevent the rubber boot from sticking to the hot spark plug.

uphoto

Appreciate it.

Shawn Stanford

Okay, so you swapped the cylinder 1 and 3 coils and you're still getting a misfire on cylinder 1.

How do you feel about your injectors? Maybe injector 1 is clogged or isn't getting a pulse?

uphoto

New update......

Got a new coil ordered to see if that's the problem and it wasn't. Now I'm getting multiple misfires!

Now I have the following codes.

P0303 Misfire cyl 3
P0307 Misfire cyl 7
P0300 Random/multiple misfire detected.

Still getting the P1248 too, that has been showing up for a year or so actually.

Any ideas? Appreciate the help.

user 83838290

Look at your engine grounding

uphoto

Really? Care to explain? Appreciate the tips greatly.

Libast

Think he means electrical grounds, which is a good idea given the age of these vehicles now