Got a Park Ultra 94' with 130k miles. smileys/smiley31.gif

Starts running ruff sometimes. By running rough it feels like it is
missing on 2 cylinders maybe usually going on a slight upgrade
hill I think but not sure. . Comes on gradually say a mile and
gradually gets rough and definite and profound by mile 2.. as I slow
down it continues through all the downshifts to a stop at the next
exit. It is gone if I stop and turn off the engine and restart.
It happens on average about 30 miles out and then about every 100
miles thereafter it fades away in about 3 more miles gradually.
Throttling it up and down dont help.

Usually on the freeway but sometimes at 20+ miles in town.

Very occasionally when I start it cold, it runs smooth and fades to a
miss gradually just a little on idle at warmup in my driveway but I
figure thats a no worry thing..

My work is close by 10min so I drive it to work without problems
regularly but some longer trips it comes back and usually with my
wife on board so she can yell OH MY GOD Whats happening. (I just smile)




Ive troubleshot this by:

Swapping Complete Ignition Module</span> with my other car.

NEW Spark Plugs and wires.</span>
(plugs were rusty on outside but tips looked really great) #6 looked a
little rich but expected that due to longest wire and I was being VERY
critical)

Disconnected the O2 sensor</span> (ran ok without it till it occured again and reconnected the connector)

Disconnected MAP sensor</span>. (the one on the air filter, (right?))

Changed the trannie oil and filter. With a little additive. TCC ? Dont
think its the TCC I Disconnected the TCC control to the trannie
(Yellow/blk wire) and got a feel for that. Its like driving with a
slipping clutch all the time.


Changed oil.. (just needed it when I got it)


Air Filter



Engine shows running at 140 Degrees. Hmmm.

(thinking about that one)



Hope the CPS isnt bad. . I cant seem to get the harmonic balancer
off. The Jesus nut is too tight for my China inpact and havent
figured a way to hold the crank firmer without buying that special tool
to attach to the flywheel. Have a new CPS waiting.

Camshaft Pos sensor would be an easy replace. (havent done that yet.)
My LeSabre kept on throwing Camshaft codes and I pulled it into a shop
and TOLD them Just change the Crankshaft Sensor ($200). Which fixed my
LeSabre. DEFINATELY..(I had already bugged and reworked the wiring to
Camshaft and Crankshaft sensors and was suprised by how the splices
were so simply done.)



Dont have a clue how to soot out a bad Fuel Injector but figure 2cyls
wouldnt go out at the same time and the plugs look great. The problem
is only happening on the road. And pretty much vanishes in my driveway.




Its a OBD 1.5.. a OBD1 with a OBD2 connector.



.

Have not replaced the COMPUTER yet.. but thinking about it. Hate to do
that .. been there.. didnt help my LeSabre's engine but did fix its
cruise control. (wonder if they will swap). But might be a good idea.



OK thats it..

Oh yah.. driving north it happens more than south..smileys/smiley4.gif Kidding





Sometimes I think theres a rat in my tank but would expect all
cylinders to be effected instead of the regular rythm feel of 2cyls
going out so I didnt think it was that.





Any IDEAS?

This one is a head scratcher. smileys/smiley5.gif



Does OBDI show engine dynamic performance with a good meter?



Thanks for any comments

No Im not going to burn it.







.










Edited by: bassasasin

Interesting find...



My Intake Air Temp sensor connector was pushed..



The connector pins on the cable were pushed back..



Could cause irregular engine changes.



Does not turn on Check Engine Light.



Maybe causing it engine roughness. Intermittently.





Good Luck

yes that should throw a code. the obd1 code says mat sensor (manifold air temp) thats the sensor at ur air box.

u should test the voltage at ur cam sensor if u suspect that....
check for continuity between the brown w white strip wire and the pin on the ign control mod. and also check the cont. of the a-12 pin on the smaller 24 pin ecu harness to the j pin on the ign control mod.

with the key on eng off, check voltage on ur cam sensor harness, between pin a-b and then b-c. both shoul be between 8-10 volts.

but, really if ur getting a reading of 140 degs, obviuosly thats not correct, change ur coolant temp sens, its only like 20 bucks. and easy to change as well.


Edited by: samueljackson

i just read that u recently changed ur w-p. the cam sensor is right near the w-p. make sure u didnt hit or pull any of the 3 wire going into the cam sensor

FIXED&gt;&gt;&gt; FIXED FIXED..


BOY AM I GLAD..


I gave it a labatomy... YEP...


Swapped out the ECM.. Luckily I had a spare..Residue from my LeSabre troubleshooting a Crankshaft sensor fix while it threw camshaft codes and new camshaft sensors didnt fix it.Gee my bad one sure looks nice and cleanthough.. the old one from my garage is nasty but runs buitimus... Lesabre ECM worked in the PARK Ultra..


I did change the IAT sensor (junk yard).. but it looked good.. and a brand new 2,4,6 ignition wire group.. same brand.. but dont think that was it. I believe in the ECM.. Had to shotgun preparing for the trip the next day. Maybe I will work back after my vacation.. here in Mt Rushmore.


ECM Makes sense ..


Just drove 800 miles on my vacation with it in two days..


Sweeet....





Thanks guys...


NOTE samueljackson.. I was seeing a source voltage for the IAT of 1.5 v.. instead of the 5v sometimes.. but it was intermittent from day to day, I didntgrab that as being a symptom as hard as I should have .


DUH..


Hope this helps anyone..

good deal glad to hear it

%#^% Now im out on my trip ... and the cranshaft sensor went out.. ..


Ran like a dream for 4 days...


Looking to limp home 7hours ... and pay ...


Seems to take off the crankshaft sensor with a supercharger is a bit tougher than without.. ..


anyway.. the sage of this P.O.S. car is continued....





Thanks all.

the actual labor of taking the harmonic bal is the same. whether u have the k,L, or1 engine.

the balancers are different for the supercharged engs tho, so dont mess urs up when pulling it off. theyre harder to find and more costly.

and like u said in ur first post, ur gonna need better than that chinese impact to get the bolt out of the c.s.. the factory lock-tite is a bich to get off sometimes.

sry to hear good luch tho.

p.s. im sure u know but still suggesting that u go thru ur pass. wheel well to do the job.

Thanks SamuelJackson... truely


Saga cont'


Ran 500 miles ok.. again... starts a little misfire when the outside temp gets over 95. hmmm.. IAT has/was already looked at and replaced cause I could.


Im looking at bad fuels.. right now.. Gonna put 91 instead of 87 for a bit. Hope that helps.


Dindt know for sure how bad the wheel was to get off.. didnt know of the LockTite.. They seem to avoid calling it a Harmonic Balancer in the manual. Maybe I will buy a good impact.. ?? $$ dont know prices on them.


Drove it today at 101 degrees... misfired occasionally, like one bump every 4 miles or so. but when I punched it it had full power.. still illusive. Im 2 tanks of gas away from 87 octane.. 87 recommended as per user manual but Im thinking im not getting it from the pumps and dont know what to expect the engine to do with bad gas actually but suspecting bad high load performance or cutting out when I punch it.


Thanks.


Thanks..

make sure to keep using 92 octane in ur sc eng. never go back to using 87. i dont care what ur manual says.