[Bob Ross]

Hi all.

Recently got a '97 Eldorado with 65k miles and just noticed the following symptoms. Didn't notice this during the test drive, unfortunately.

1. When car is in gear (D,3,2,1,R) with engine running, and the car is stopped with the brakes depressed, it will stutter a bit, like it wants to move forward. Can't tell if it's a misfiring or not (I'm no expert), but there are small "pops" accompanied by slight vibration. When in neutral, the engine runs smoothly. Once I press on the accelerator and the car starts moving, the engine runs smoothly...EXCEPT...

2. Sometimes, while at highway speeds, the stuttering will start up again when I accelerate. Does not happen all the time, nor while cruising at constant speed, nor at lower speeds.

I've pulled the codes and had no current codes. I cleared the history a few days ago and no codes have popped up since. The "service engine soon" light came on shortly after I filled up with gas. I suspect the dealer put regular in it while I used premium. It went off after I tightened the gas cap and cleared the codes.

I've searched the forums for advice and here's what I plan to do this weekend:

1. Replace spark plugs and wires (AcDelco 41950 & 9748J).
2. Clean throttle body.
3. Clean IAC (if that doesn't work, replace)
4. Clean EGR

Any other ideas on things to check? I really like this car and am hoping I can solve this issue myself. Thanks!

 

[Ranger]

:welcome:

I'd suspect it's time for a set of plugs and wires. Stick with A/C Delco. Gas has nothing to do with it. The car will run perfectly fine with regular.

 

[Bob Ross]

Yeah, I didn't think the stuttering was due to the gas. I just thought the Service Engine Soon light might have been caused by that since the owner's manual says the light can pop up temporarily if you switch the quality of gas, until the system adjusts.

So I can really just use regular gas? That would be nice since it'll save me some money but I'd rather spend the extra for premium if it'll save me on maintenance or repairs in the long run. 90% of my driving is highway driving to and from work so it's not like I'm trying to achieve peak performance or anything. If I can double the mileage on this car, I'll be happy. If I can triple it, I'll be ecstatic.

 

[Ranger]

The Northstar has a very effective knock sensor. When it detects spark knock it will retard the timing accordingly (you'll never hear it). If you are going to race the car and want every last ft/lb of torque, use premium. Otherwise regular is just fine and I'll bet you can't tell the difference. I used it in my '97 for years and saw not difference in performance (even at WOT) or in mileage. Octane has absolutely no affect on maintenance or repairs. Do a search for "octane" if you wan to read more. This subject has been beaten to death over the years.

 

[Jim 99 eldo]

I get this issue every now and then I believe it is the seal/bushing issue they have talked about with the torque converter I am almost sure this is an early sign of that failure. Does you car leak trans fluid at all even a little bit anywhere near the inside of the left front wheel? When you cleared your history codes did you have a PO741? What you are explaining is not a tune up issue

 

[Submariner409]

If I can double the mileage on this car, I'll be happy. If I can triple it, I'll be ecstatic.

Depending on which Eldorado you have (ETC, ESC) there are two different HP engines and different final drives. (Update your profile ^^^)

Generally, the ETC will have a 300 hp engine with 3.71:1 final drive. In good tune it will return 12 - 16 miles city, 16 - 21 miles suburban/commute, and 24.5 open Interstate on 87 octane Top Tier gasolines. (Google)

The ESC will have a 275 HP engine with 3.11:1 final drive (economy/highway gear) and will return the same 12 - 16 miles city, maybe 17 - 21 suburban/commute, and 27 open Interstate.

If ANYONE in here could better any of that by even 1.5X we'd all be ecstatic.

 

[Bob Ross]

It's the 275 hp version. Did they even use the term "ESC" in '97? All I'm finding is "ETC" and "base" for that year.

Regarding the mileage, sorry I guess I used the wrong term and should clarify. I meant total miles on the odometer. It's got 65k miles now. I was meaning doubling or tripling that (130k, 195k). Point being, I'd like to drive this car for a while.

 

[Bob Ross]

I get this issue every now and then I believe it is the seal/bushing issue they have talked about with the torque converter I am almost sure this is an early sign of that failure. Does you car leak trans fluid at all even a little bit anywhere near the inside of the left front wheel? When you cleared your history codes did you have a PO741? What you are explaining is not a tune up issue

No PO741 code. No trans fluid leak either.