Hey everyone... ive browsed posts upon posts on this forum to no help, and still cant figure out this problem. The business has thrown numerous parts at it and it STILL doesnt run right...


#1.
State the problem in its completness and correctness, the car model and year, etc.
When it is a driveability mal-fuction relating to engine/trani/drivetrain,
provide the CODES, always provide the CODES! Buy, borrow, rent a code
reader. CODES PLEASE !

1999 Cadillac Catera. 3.0L V6 with Electronic Throttle Control
Oh... you want a codes list? there have been sooo many damn codes i dont even know where to start.
* Random Misfires
* all cylinder misfires with no consistency, but the latest has been cyl 1,3,5, & 6 (p0301,303,305)
* runs and idles rough.
* idle likes to wander, from 400-800, sometimes it kicks up to 1500 or 1800, sometimes it likes to stay at 1200 for about 10 seconds and then starts to wander again.
* i do not know the code, but some time ago it once had a Secondary Air Injection code.
* if i rev it up to 2500 the idle will still wander around 2500... sometimes 3000, sometimes as low as 2000

#2.
Tell us when the problem occurs: driving, starting, parking, cold weather, hot weather,
when your aunt drives it, when it rains, when you hit 46 mph, when you touch the wipers,
when you sneexe, when the planets are in line, etc .. you get the point?

its all been in idle, parked in the shop. Out on a road test the thing has GOOD power, nice acceleration, excellent torque, and runs like a charm!
problem used to happen only during cold start up and once warm it settled out and was normal. Now after ive done more work to it she stumbles cold or warm


#3.
NOW, THIS IS REALLY IMPORTANT .. PLEASE TELL US what you have done so far
in trying to resolve the problem - then read #1 again.
IF nothing, say that. I cannot think of anything more frustrating than we start making suggestions and
we get a "done that." Me for one, usually take a deep breath, walk away, and I dont come back to
that thread again. Other TECHs may be more forgiving or have more time, I dont.

Intake gaskets changed
Upper plenum o-rings changed
Valve covers changed
Coil Packs changed
cleaned out the PCV system
cleaned the Intake Resonance Switch Over Valve
Cleaned out the intake tubes and duct work under the throttle body
cleaned the throttle body
replaced the mass air flow
redid ALL the vacuum lines - double and triple checked i had them routed correctly
pulled the 135 coil pack out and grounded the plugs. pulled the FP relay and cranked the engine to see nice, hot spark jumping the plug gap
ive tried spraying brake cleaner everywhere to see if the idle would change... nothing
ive even tried straight propane on a hose and feeding it to areas around the engine... nothing
timing belt has been changed
water pump has been changed
tried the relearn process for the ETC MULTIPLE times to no avail
seems to run a little bit better if you unplug the MAF, but like i said... its brand new. and the old one did the same thing.
if you mash the throttle when in idle - she almost sounds like she bogs down. You get a nice growl from the intake tube. I have removed the airfilter and box to eliminate air delivery problems
took a mightyvac to the PCV system when the intake was off... created good vacuum and could hear it trying to suck air past the piston rings when you listened down the intake runners

* i have not bought a throttle body with the internal TPS because they are upwards of $350. And thats a far cry to **** in a bucket to probably see the thing not run correctly anyways

#5.
On some issues, specially with A/C & airbags, we are very reluctant to provide suggestions unless
the owner can convince that he/she knows what he/she does with such devices.

Trained technician... and yes i know what im doing. NOTHING is out of the question here. Ill try just about anything!

 

I have a rule... Never trust anyone elses diagnosis or repair work.
So today i plan on tearing apart the front timing covers and so forth to check the timing just in case something might not be lined up.

If anyone has an Electronic Throttle Body for sale i would be more than happy to consider it.

 

timing belt had a bit of slack in it on the 135 side between the crank and tensioner. Ive tightened it up and doing a compression check at the moment.

 

Talked with one of the guys at GM. after they said they could loan me the timing belt alignment tool kit, i ran there only for them to tell me i cant leave the shop with it. WTF

anyway - one of the techs i was talking to said that theyve seen some pretty weird stuff with the catera - and its a possibility that the cat might be restrictive. Makes sense seeing as how the STFT is going...

 

Sorry - i guess i forgot to mention
STFT both banks +28%
LTFT -0.8%

 

you start by resetting all the codes and then note down the NEW codes ...



.

 

Yup. Done that... Just waiting for the NEW codes list after i put it back together. Like i said - the most recent "codes list" are Random Multiple Misfires on cylinders 1,3,5 &6