: Rough idle at start-up



Dadillac
06-18-06, 06:26 PM
When I start up the Seville, it will idle roughly (always first time starts, warm or cold outside temp). As soon as I put it in gear, and start to move, it smooths out. Then, it will be smooth from then on out. If I start it, and it is running rough, and I give it some throttle while still in park, it will continue to run rough. I am thinking FPR, but the gassing it, and the issue remaining, has me confused. There are no codes set when this happens. Any thoughts?

Don

RUDEINC
08-15-06, 06:51 PM
I get this exact same thing with my 99 deville northstar. I start it up after setting in the garage all day, runs a little rough, pull into street and drive up to the stop sign (about 900 ft.) and no more rough idle. But if I just sit in garage for a little bit, it continues to run a little rough.

100
08-15-06, 09:33 PM
I don't even own a N* powered Cadillac, but I have an idea...

On my car, the parking (emergency?) brake is controlled by vacuum and it is controlled by the shift lever. If yours is the same way, maybe those part has some minor leak or sealing problem there. And as you applied vacuum, the actuator seals up and it will not longer have a vacuum leak... What do you think about this theory?

Elmer Fudd
08-15-06, 10:06 PM
I don't even own a N* powered Cadillac, but I have an idea...

On my car, the parking (emergency?) brake is controlled by vacuum and it is controlled by the shift lever. If yours is the same way, maybe those part has some minor leak or sealing problem there. And as you applied vacuum, the actuator seals up and it will not longer have a vacuum leak... What do you think about this theory?


I like it (even if it isn't the case),my Lincoln had a parking brake release that was vacuum. Do you hear any hissing down by the manual release????

Ranger
08-16-06, 09:26 PM
Don's car is an '02. It has an electronic parking brake release. Check the FPR. It's easy enough to do.

100
08-16-06, 09:36 PM
Don's car is an '02. It has an electronic parking brake release. Check the FPR. It's easy enough to do.

I am learning more here! That's kind of good idea. Pulling vacuum all the way in the car and having more gimmicks is more problematic, I suppose.

Tommy Trojan
08-21-06, 02:16 PM
Carbon buildup. Do a little WOT and/or add BG 44K and clean the throttle body. The rough idle will go away most likely

Dadillac
08-21-06, 05:51 PM
Well the car still has this issue. I checked the FPR, and it doesn't leak. My throttle body is clean enough to lick it. Carbon build-up? Are you joking? I am quite certain that my engine is carbon free. This isn't a big issue, just an annoyance. I have been tackling the minor problems with the car, and wanted to see if anyone has an idea. If anyone has any input, please post. Thanks

Don

ejm74
10-27-06, 09:12 AM
i have same problem. i got 1998 cadillac deville starts rough and then smooths out when gets warm dont know what it is...

fpmesiIII
10-27-06, 08:10 PM
If its not the FPR and throttle body cleaning doesn't help it could be leaky fuel injectors.

Ranger
10-27-06, 08:14 PM
Coolant level holding steady?

eldorado1
10-27-06, 08:29 PM
Carbon build-up? Are you joking? I am quite certain that my engine is carbon free.

Pull a spark plug and find out for yourself....

I bet you haven't been doing your "italian tune ups", have you? :rant2:

ejm74
12-18-06, 09:13 AM
did you find out what the problem was with the car. thank you eddie

I_Finally_Have_A_Cad
12-18-06, 11:00 AM
Someone else poked at this; I wonder if it has to due with pulling away and higher rpm/speed helps or if a warm engine helps it out. Check to see, because there are a whole bunch of things it could be if this is the case.

Raze
12-19-06, 06:07 PM
I had this problem back a year ago, as Ranger asked previously, is the coolant level holding steady? My car had a partially leaking HG that allowed just enough coolant in to foul one of the cylinders leading to a really rough startup when the engine was cold. As soon as everything warmed up and the block/head expanded and closed the gap it ran smoothly. I tried everything else, coilpacks, wires, plugs, FPR, injectors, carb clean, WOTs, cleaning the MAF, nothing worked. Then after about 2 months of this i recieved the dreaded "check coolant level" and had it dye tested. It barely showed any combustion products so I had my shop do the 'proper' leakdown test as the Bbob had described it, and bam coolant in a cylinder.

caddyman2005
12-22-06, 09:36 PM
on the 2002 look for a vacuum leak at the intake manifold plenium where it meets the coolant crossover there is a bellows that leaks. If that is leaking it will have to be replaced. The fuel pressure Regulators leak on all N* but is not as common on the 2000 and newer. If i had a 1995-1999 N* with a cold running rough problem I would replaced the Fuel Pressure Regulator First.

cost
12-26-06, 02:08 AM
Hi: i have a 95 Eldorado touring etc, about 5 months ago my caddi started with the same issues you posted, but yesterday service engine soon appeared and the codes show a egr valve, but holidays and me being in mexico and no dealership in 500 miles away will delay even more repair :crying2: i will update when i clean the egr valve

dp102288
12-27-06, 02:12 PM
^^ Well do keep us posted. Is there not even a store with the cleaner in your area?