: flashing check engine.. shakey idle - 96 sts



DannyV
11-20-04, 06:42 PM
Hi all...

new to forum.. having some problems w/my 96 sts.. I have 102k on it and recently the check engine went on. When the problem first started, the car was having trouble accelerating when I would press the gas.. the RPMs wouldnt rev and the check engine light would start flashing.. Now, the check engine light is on all the time.. Since this the problem started, the cars idle literally shakes the car and the car is defiant to accelerate. When Im cruising on the highway, the check engine light will occasionaly start flashing @ me.. I know this is no good but have no clue what the problem is.. I just changed oil but the problem persists.. can anyone help me out here?

thanks

Dan

Ranger
11-20-04, 08:15 PM
If the SES (service engine soon) light is on then a DTC (diagnostic trouble code) has been set. Simultaneously press and hold the OFF and PASSENGER WARMER buttons til all segments of the DIC light up. The DTC's will be displayed on the bottom as current or history. Write them down and post back.

DannyV
11-20-04, 08:29 PM
thanks for the reply.. heres what i got.. the only current code is PC0300. i didnt bother taking note of the codes in history however @ the end of the sequence, it displayed "PCM?" .. no clue what that means.. thanks for the help in advance..

Dan

DannyV
11-20-04, 08:56 PM
i know its a misfire.. what can i do about it?

chazglenn3
11-20-04, 09:24 PM
Probably plugs and wires. When it displays PCM? it is asking for your input. Push the "auto" button to exit.

mastertech
11-21-04, 02:17 PM
When your check engine light is flashing, that means there is a potential catalyst damaging event taking place, such as multiple misfires. A misfire will dump raw, unburned fuel into the exhaust, therefore into the converter. You would do well to change your plugs and wires at this stage before you clog up the converter, if you haven't already done so. Good luck!

zonie77
11-21-04, 10:33 PM
You might have seen this recent post already...

http://cadillacforums.com/forums/showthread.php?t=25659

Definitely change plugs and wires asap. It's cheaper to replace them yourself than to have the dealer diagnose it first!!!!!!!!!!!

zonie77
11-21-04, 10:38 PM
Another recent post.

http://cadillacforums.com/forums/showthread.php?t=25119&page=2

DannyV
11-22-04, 06:02 PM
alright heres what i did.... replaced all the plugs and wires.. good thing, the check engine went off and the idle is a bit better. I took it for a test drive and noticed that the acceleration was still hesitant; in fact it was pathetically hesitant... i tried punching the throttle and the engine revved up but the car barley accelerated.. when I drive the car conservatively, it drives okay but when i give it some gas, its reluctant to move like it should.. so, what’s going on here?? Would crossing of the wires yield this type of problem? could it be the fuel injectors (please tell me no as this will cost $1200+) any help is appreciated.. thanks in advance.

DV

STS 310
11-22-04, 06:08 PM
Engine rev, but no power to the wheels? Possibly the tranny solonoids. But that would throw a code woudnt it?

DannyV
11-22-04, 06:19 PM
I was thinking tranny related as well but the car does move when I drive it normal.. It's just when I punched the throttle that the car didn't much accel. again, no current codes.. when i put the car in neutral and rev the engine, everythings sounds/seems okay.. when it goes back to idle there is a slight stutter but idles fine after that.. im in the dark here :suspense:

sts96
11-22-04, 08:04 PM
Do a fuel pressure check while driving, could be partly clogged filter fuel or air filter. injectors can be had as a full set for very low cost from a salvage yard. lol sts96

Ranger
11-22-04, 10:25 PM
Would crossing of the wires yield this type of problem?

DV
NO. I just replaced my wires and after having them all installed I removed the right bank off the coil packs again to get a neater routing. While reinstalling them I crossed two of them and the rough idle was quite noticable. If you crossed any wires, you'd know it immediately. Sounds like the trans is slipping to me.