93 regal misfires (tail pipe explosions and smell)

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access to the sensor / balancer is quite easy even without removing the wheel, just turning it right. however it's not a 28mm socket as some books say. the problem is that i cant unscrew it - the engine rotates.

i decided to let a shop exchange the crankshaft sensor for about $140. hopefully that will do it.

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it worked perfectly with the new crankshaft sensor! for a few days... tues/wed/thurs/fri about 20 miles each day but now friday evening it started doing it again on the way home and in the parking when i got there. after i let it sit for half an hour i checked the codes and 17 was there again.

started it up again and it died rightaway. then started again and it ran - rough and vibrating.

so i removed the battery for a few minutes and the car started fine. it was rough for a few seconds (idle re-learn...?) but then it settled. no code 17 anymore and the test drive was fine. it idled 15 or so minutes without issues.

is it possible that the spark plugs create this code 17 error? or possibly were they fouled by driving when the sensor was bad and misfiring? maybe the IAC is bad and doesnt allow enough air which chokes the engine and causes it to think its due to the spark reference? did the shop screw me over and not change the sensor (cant see due to the balancer and the sensor protector) and put in a bad crankshaft sensor?

if not - what can give code 17 on this type of car? and how come removing the battery helps?

i would really appreciate any help - i'm at a complete loss. this only started in july when i posted and got really bad this monday when it stalled 6 times in a day! please help!

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i tested the EGR with 9 Volt battery (A+ and B, C, D on -) it clicked on all. coil values pretty close to this post: http://www.automotiveforums.com/vbul...88&postcount=2

then I checked the coils and they are OK (between 5-8Kohms high voltage and 1.5 ohms low voltage side).

i took the ignition module to Murray's for testing. it tested all green. however the car isnt starting anymore now, its just turning over... i hear the pump pressurizing the system and the exhaust starts smelling like pure gas after a few tries. there is no spark on the coils while cranking (removed one of the boots at a time to see if there's spark)... the computer only has code 12 which is "OK"...

this is getting better and better.

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i took the ignition module back to murray's and they tested it again - it was always good.

turns out the ignition module was not grounding to the plate on which it's screwed on. there was lots of oxide and some dirt on both the ignition module back and the ground plate behind it (i think it's also a heat spreader). i used sand paper to clean and then put petroleum jelly on the bottom to avoid new oxide forming. also put petroleum jelly on the low voltage and high voltage connectors of the coils. the car started rightaway.

however now that the car is running i don't think my initial issue - idle stalling - is fixed. haven't had it yet but it would be too good to be true - that the ignition module was not getting proper ground and thats why it would cut off and not supply the computer with spark reference...

still planning to do a EGR valve cleanup and a vacuum check. never done either so wish me luck...

as usually any input is appreciated on what to test next - but i'm assuming that either ppl don't care about this thread anymore or those who know the car stuff are all on vacation or too busy to check the forum.

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i just discovered another symptom! don't know if it's related but...

if i brake very hard the rpms go down slightly while at idle. so if i'm in park with the engine warmed up after test drive and 900rpm idle, then i press the brake pedal very hard twice in a row the engine rpm goes down to 700 (i'd say) and i can feel a hesitation. it doesn't die and goes right back up to normal, but it's just odd because i never noticed/cared about it before.

is this an indication of a power brake issue, a vacuum leak or just a normal way of reacting because i'm using up the available engine vacuum quickly?

just to mention the idle stall happens mostly while sitting at a light, just barely holding the brake.

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the car ran fine today but i pulled code 17 from the computer again. i assume this is another stall waiting to happen... i dont understand what else than what i've already checked/changed can cause this code. Knock sensor? vacuum? camshaft sensor?