Rough start and a bad Idle that turns into a stall


May 12, 2013
Hey guys,

I've been searching around to see if anyone else has had similar issues and found one thread that kind of fit the profile but ultimately had no true solution.

The same problems I started with when I got the car are still present and I'm pretty much out of ideas. I'm trying my best to handle everything I can myself and with the help of a few motor savvy friends and DavidM who was one of the first members of this site to welcome me in.

Here is the scoop; first, the start up is rough. The car cranks but has trouble starting. I try not to force the starter to crank for more than 3 seconds before I stop, pull the key out of the ignition and start again after a few more seconds. Most of the time it starts on the second or third attempt.

Next thing, she is running rich beyond my wildest dreams. I can smell my gas money just evaporating into thin air :eek:.

Now... we've started the beauty, burned a quarter tank of gas getting there and now, we are waiting for her to warm up to 160 before take off. TPS is at a firm .42, my IAC gets down to about 28-30 as the car warms up some more. Then, my idle just start yo-yo'ing. About once every 12 seconds my idle drops to about 400-500 causing my engine to move about under the hood and some black water/oil (No real sent a little oily to the touch) to spurt out of my exhaust.

Then comes the stalling, this isn't too frequent but enough to ask about. Mainly happens after driving for a while, more during stop and go traffic. And always during one of my idle drops.

All my numbers seem right... I've changed the spark plugs to Autolite 24's gap'd them to .032- a tight .035. I bought and installed MSD spark plugs wires, even cleaned the coil pack, and still my starter gives me hell.

I cleaned my throttle body as best as I could without removing it since I didn't have a new gasket to install. But it was a night and day change, just didn't help the idle at all. I swapped out vacuum lines that where clearly in need of changing, even switched to a new billet vacuum block thinking that maybe my stock plastic one was leaking from compression or cracking over the years. Still nothing.

So here I am, back at square one. Anyone have any suggestions? Thanks in advance.

More info is needed. What are all the mods that are done to the car? Chip, injectors, turbo, fuel pump, etc......? Update your signature with all the modifications that way you dont get asked again. Give us all your scanmaster numbers and fuel pressure reading.
What is your vacuum at idle.
Did u ck the coil om's should be 11-13
Do u have vacuum brakes?

Posted from the TurboBuick.Com mobile app
" to warm up to 160 before take off. TPS is at a firm .42, my IAC gets down to about 28-30 as the car warms up some more. Then, my idle just start yo-yo'ing." Sounds like a closed loop idle issue.

Fresh O2 sensor?
O2 cross counts are?
Fuel psi is?
Cracked header tubes, x over connection leaks?
Time for a spring cleaning process.
Original cat converter still on the car?
I would second the bad MAF. If it is original, you should replace it anyway for peace of mind. Go to Full Throttle website and check out their translators.
To give a little more info on George's car.

I swapped my MAF into his GN, reset and let it run for a bit. No change so we ruled out the MAF.

Moved to the O2 sensor which was pretty bad. Replaced with a Denso.

Alot of dry rotted Vacuum lines, I think he took care of that.

No Exhaust leaks. Driver side Header is aftermarket. I think passenger is stock if I remember right.

Chip is TT 5.7 burned for his completely stock combo with 28lbs injectors, stock turbo etc.

New Autolite 24s with new plug wires.

I believe George has a Adjustable Fuel Pressure Regulator, Fuel Filter, Fuel Pressure Gauge on order. Fuel System has a hotwire. Not sure on Fuel Pump as the tank was full when he brought the car over.

No Vacuum brakes, they are Powermaster.

Cat is in good shape (exterior)

Posted from the TurboBuick.Com mobile app
Also just remembered, the coil pack has a 1987 sticker that looks to be like a MFG date. Not sure if George checked the coil pack or ignition module.

As far as the starting problem. I believe it to be the starter. When I looked the car over it would start on the 2nd or 3rd attempt and sometimes on the first attempt. There was once where it just clicked a few times and would not turn over. So either the starter or bad connection at fusible links?

Thats all I can remember, if anyone has any suggestions please let George know. I've been pretty busy lately. He just bought the car and hasn't been able to enjoy it. Lol

Thanks guys

Posted from the TurboBuick.Com mobile app
Start the car with the MAF disconnected, see how it reacts. Check to make sure the EGR is not stuck open or the EGR solenoid is closed all the time and or solenoid filter is not clogged. A nice scan tool will help a lot. You need to see what the ECM is seeing.
Sorry for the late reply guys. I was put on a surprise communications exercise and have been pulling 15+ hour days in what feels like a billion degree heat. Anyways, @ DavidM thanks a lot for adding all the info you did, you are always a great help.

Just to clear up a little bit I do have a PTE Adjustable Fuel Pressure Regulator w/ 0-100 PSI Pressure Gauge on order, I should have them in less then a week.

Next I have a new AC Delco Fuel Filter on hand that I need to instal, It''ll be on the car today or tomorrow. I also have a lot of the fluids and gaskets needed that are mentioned as part of the spring cleaning, I just need to get my butt over to the Auto Skill Center to get most it done. In case anyone is wondering the Auto Skill Center is a place where I can rent a bay w/ lift for $7 per hour. They have every tool on earth and I can borrow those at no extra charge. I live in an apartment complex and I'm not "supposed" to work on my car in the parking lot.

I was planning on going to O'Reilly's today to get my starter, and coil pack tested. See if those parts need replacing. But with the way the car is running I'm scared to take her anywhere.
These are my latest ScanMaster readings in park after driving for about 30 minutes. DavidM and I changed out the fuel filter and transmission fluid, gasket, filter. I also got a new Optima battery since when I got to Autozone for testing they told me my battery was bad. Starter and Alternator passed test.

O2: Jumps from 100-899
AF: 04
L8: 30
Bat: 13.6
Int: 128
Bl: 119
Clt: 170
Ats: 109
r: Jumps from 500-900
tps: .42
IAC: 29
cc: 17
Mal: 00

Thanks in advance for any and all help.

Night everyone.
Guys, like George stated I helped him finish up his spring cleaning. Installed a new fuel filter and dropped his transmission pan.
We put a multi meter to his Coil pack. 1 and 4 put out 11 ohms. 2 and 5 put out 0 ohms and 3 and 6 put out 0 ohms. This is with key on car off.

After resetting his ECM his car had a smooth idle and no RPM jump.
Iac was at 16
Tps at .42
CCs moving as they should
AF 5
INT 128
BLMs 128
RPMs holding solid at 750

After driving for a bit, that is when the idle issue returned
There is also a bit of water coming from his exhaust. More than your usual condensation. George is going to drive a bit and monitor his coolant level and check his plugs. Oil looks good.

Posted from the TurboBuick.Com mobile app
I think we need a pic of your dog.


Posted from the TurboBuick.Com mobile app