Misfires, rough running engine (very). Doing a compression test.

[strobhen]

Here's the situation.

Driving down the road at 35 mph, car running very smooth like it has for quite some time. Have a sudden loss of power.

Engine gets progressively more loud, a pulsing sound. Car begins to shake. SES light begins to flash, and comes on solid. *Huge* loss of power and am unable to rev engine (though I certainly did not slam the gas). The car has produced no smoke.

I pull the car over, have it towed home.

The coils & plugs are 1 month old, the wires are 3 months old and not burned. Car has 40k miles (way too early for engine damage... I hope...).

So, step one, pull all the plugs.

Most of them are very black. *Might* even have oil on them, Its hard to tell. If they do, its not much.

I checked my oil, it looks fine, no coolant, level is fine.
Checked the coolant, looks fine, not low and no oil (though I have not drained anything else).

SES light is still on (checking it tomorrow, I am going to try & rent an autozone scanner since I can't get a registration # for my obd-2 scanner, anyone have one? It would be very, very helpful).

I will also be performing a compression check tomorrow.

To anyone that has done a compression check: Any tips? About what is the proper psi for the L36?

Anyone have any hunches at all as to the problem?

Car has been running perfect up until Thursday night.

Thanks for any help or suggestions in advance.

I will be posting all results & data I can get as I get it.

[Fierdon]

Mine did that once, but it was the altenator. It would jerk if I tried to speed up, but the electricals all dimmed down and started to shut off. Not sure if thats your problem, but I've never done a compression check. Good luck finding out what the problem is, hope you fix it soon.

[strobhen]

Thanks,
Don't think it is the alternator though, no dimming of lights & the gauge is acting normally.

[99W68Firebird]

hey, funny you bring this up... i am having the same exact problem right now.. yesterday went to get oil change.. left and yea how funny is it when you get to 30 mph and floor it.. a tricycle could beat us right? well i took my car back to oil shop and had them check it out and they just said everything was fine, which i know it wasnt.. so bought some fuel system cleaner put that in.. then SES light finally came on lil bit later. took it over to my maintenence guys house so he could scan it and it brought up that my 3rd cylinder had misfired 1206 times, so im guessing spark plugs or wires either time to go or was coincedence it happened right at oil shop and somehow they messed up something. but if you find out how to fix yours plz let me know.. guy who does my maintenence is busy for the next 3 weeks and he is installing my headers, cat, and catback in 3 weeks so i need to find out how to fix it before then.

[strobhen]

Alrighty, not doing a compression check just yet. Don't want to have to purchase the kit if I don't need to.

I was able to get my scanner working, pulling down mulitple random misfires.

Going to be diagnosing that route here for a bit.

Leaning towards the ICM right now, but not sure.

I am fairly certain its not the cat (it's not rattling anyway).

[RallyRed 98]

put $100 on ICM to win

[strobhen]

Wow, surprise of my life...

It was a coil...

Note to those that read this. On the rest of the forum, in other messages, you will get the impression that coils generally start to fade before they go out. This is not always true. The coil was working 100% one second, and within 10 seconds it would miss *at all rpms*.

Coil, like I said, is one month old. An MSD. I plan to try & have it exchanged on warranty.

Don't have bad feelings towards MSD for it, stuff happens, not every product will come off the line perfect. As long as they replace it, all will be cool. If they don't, well, they will lose a customer. I'll let everyone know if they do.

Definitely wouldn't have thought this from the other posts on the forum.

Goes to show how critically important a good scan tool is to diagnosing a car!

[RUC]

I had the exact same problem, but it ended up being the fuel pump.

[RallyRed 98]

i was in a drive-through at mcdonald's and the car just cut out... ended up being the ICM. i almost died myself.

i guess those things are go or no-go, but maybe it had been dying all along. the TSB says that water gets down in the casing somehow and freeze-thaw cracks it.

[99W68Firebird]

what would cause loss of power after getting oil change?..or is it just coincidence that i need a tune up... because all yesterday the car ran like crap.. then today SES light went off and it ran fine and i was driving it hard and it really didnt give me any problems.. then i turned off TCS and hit it and it did that loss of power crap again.