'93 STS With "shuddering" ---HELP ME!!!!!

HappyMofo

HappyMofo

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Hi, Im new to this forum, and also a new Caddy owner. I recently bought the 93 STS 4.6L V8 which has 129,000 miles on it for $6000. (what a steal!) Almost perfect interior, body, and paint.

Anyway, I noticed when i test drove it, that it would shudder from time to time :feedback --(I would go say, 65 and it would fell like rocking forward then backward but still go 65.)

I have given it a tune-up with OE acdelco sparkplugs, (6.50 a pop), fixed the timing, flushed the radiator and tranny, and changed the fuel filter/airfilter.

Any suggestions???--because it still is shuddering. I think it might be the trans. (praying not tho) as it seems that the engine is fine...(25-28 mpg and purrs like a kitten)... Im baffeled? I dont think that its the injectors being clogged either...

I used castrol dex III tranny fluid (compatable to the dex IIE), and was wondering what it could be since this is my first Cadillac and the first time this has occured with a vehicle Ive owned.

Any help or suggestions please as I do not want to go into the dealer and spend 80 bucks an hour. :feedback
 
No, its not much help.

You dont describe ths shudder much - but first thing that comes to my mind are the tires / suspension. You may have tires that need to be balanced or need an allignment - have you considered those possibilities?
 
ya, ill give ya more info...my bad.

this shudder is like this... when i am driving with hard acceleration no problem, or when im slowing down nothing. It happens with a constant speed...

this shudder or rocking is like a lurching forward. Kinda like if you push the bumper from the back of the car when its in park, but im moving. When im going down the road at 65, with the car in drive, it lurches. If i throw it into neutral while going the lurching stops.

I dont think its the tires, but I do need new tirerods maybe because when i hit 75+ mph the steering wheel shakes hard--not left to right but like going over a bumpy dirt road shaking.

I am also wondering if its the transmition mounts... cuz i seen on another forum that if they wear out (cuz theyre rubber) that the tranny could rock and the car could shudder.

I changed the Oil, air filter, fuel filter, gave it a timing with tune up, and flushed the coolant... and it still lurches... Im out of ideas except for the tranny... :slam

Any ideas bro?
 
mine started to do the exact same thing and i ended having to get a tansmission that was about $5,000, i hope thats not the problem with you. :C
 
was it a complete rebuilt...what was wrong with it-- did they say specifics?
 
Try tossing a bottle of Lucas Transmission Treatment in the tranny. If after a few days the problem is still there, then the tranny probably isnt the problem and I would go back to suspecting the suspension / wheels.

IF the shudder improves after the treatment, then you need to be very strict on the tranny maintenence because its about to go bad.
 
ill try it and let ya know... the 5 bucks for the bottle is worth a try compared to the alternative of 200-5000 dollars.

thx, ill keep ya updated... ill have pics of my ride by tomorrow also. :dancefool
 
quick info...im going into the dealership to have em hook up there computer and diagnose my tranny/ car/ SERVICE RIDE CONTROL that just popped up...ill keep ya posted.
 
Surging at steady throttle

HappyMofo said:
quick info...im going into the dealership to have em hook up there computer and diagnose my tranny/ car/ SERVICE RIDE CONTROL that just popped up...ill keep ya posted.
Click to expand...


One thing that will cause the STS to surge back and forth while holding a steady throttle is loose dogbones. The dogbones are the mounts or steadyrests that hold the top of the engine steady - they run from the front of the engine forward to the body.

If you replace those, there is a very good chance that the surging will be cured.

wallyp
'93 STS
 
HappyMofo said:
Hi, Im new to this forum, and also a new Caddy owner. I recently bought the 93 STS 4.6L V8 which has 129,000 miles on it for $6000. (what a steal!) Almost perfect interior, body, and paint.

Anyway, I noticed when i test drove it, that it would shudder from time to time :feedback --(I would go say, 65 and it would fell like rocking forward then backward but still go 65.)

I have given it a tune-up with OE acdelco sparkplugs, (6.50 a pop), fixed the timing, flushed the radiator and tranny, and changed the fuel filter/airfilter.

Any suggestions???--because it still is shuddering. I think it might be the trans. (praying not tho) as it seems that the engine is fine...(25-28 mpg and purrs like a kitten)... Im baffeled? I dont think that its the injectors being clogged either...

I used castrol dex III tranny fluid (compatable to the dex IIE), and was wondering what it could be since this is my first Cadillac and the first time this has occured with a vehicle Ive owned.

Any help or suggestions please as I do not want to go into the dealer and spend 80 bucks an hour. :feedback
Click to expand...





Hey fellow Santa Barbara County dweller. :dancefool


I have a 1986 Cadillac CDV Fleetwood.
 
Go to the Chapter Forum in the WESTERN Chapter and see the re-post on the meeting up for caddys and lincolns of our area.
I was just thinking we should get something going for our area.

1986_MarkVII said:
Hey fellow Santa Barbara County dweller. :dancefool


I have a 1986 Cadillac CDV Fleetwood.
Click to expand...
 
Problem Discovered!!!!

The problem is not the tranny as I thought it was!

It is the fuel pump going bad. I havent replaced it yet, but Im pretty sure thats the culprit.

The trans. is fine, i changed out my radiator,(thinking the trans. oil was mixing with the coolant) and thusly changed my trans fluid again. Its fine, and the tranny had no shards or debis in the filter or bottom of the pan.

The surging is from the pump sometimes hitting bad burns on the motor, as when im going up or down a hill.

thx for all the help with the posts though, because it gave me guidance while i was snooping.

:invasion:
 
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