engine stalls at stops

[PFA]

So far, after moving the #8 COP, I haven't had any issues of stalling. I would have to say that was my problem. I am now having a miss every now and then.
I had a broken IMRC cable too...just happened. Luckily, I had another setup with the engine I bought and got it on.
Just have to wait for it to throw a code. I'm not thrilled about taking off the intake for the back 4 coils. If I remember right, it takes about 2 hours to take off and back on....

 

[SHOZ123]

Here's some tips to make taking the surge tank off easier the next time.

I get rid of the support strap on the drivers side in the back.

The passenger side strap has the ground strap on it. When the tank is off take the bottom stud out and use it on the top of the tank strap. Be sure to put a washer between the ground strap and the top nut on the stud. Makes this all much easier next time.

You do only need to take the tank and the attached runners off as one piece. Just loosen all the rubber couplers and push it off.

 

[JoesSHO]

Coil(s) are dying. Especially if you have to cycle the key all the way off.

x2 on Paul's strap idea. Saves a bunch of time.

 

[mustangracer91]

another issue which nobody has mentioned is the EGR valve, I'm not familiar with the one on these vehicles, but I know that an EGR valve that's stuck open will cause stalling issues, and usually when coming to a stop after the vehicle is warmed up. If the egr is vacuum controlled, a simple hand pump on the valve while the vehicle is idling will tell you if it's sticking open or sealing. If the engine dies or stumbles when the valve is open, then it's working at least somewhat. If there is no engine running change when the valve is opened, then the valve is sticking open...

 

[JoesSHO]

Only thing is that the exact symptoms/stalling/cycle the key, etc... has coils written all over it. Next time it stalls, try starting it without turning the key off. When my coils were going, it would not start unless you cycled the key all the way off and then restarted it.

 

[PFA]

I do believe this was my case. I still have the slight miss. Is there anyway to narrow that down? This is occasional and usually under load. With no code being thrown, I'm not sure how to nail down which it is.

What is the ideal way to bench test a coil?...or isn't there one?

Thanks all!!

Only thing is that the exact symptoms/stalling/cycle the key, etc... has coils written all over it. Next time it stalls, try starting it without turning the key off. When my coils were going, it would not start unless you cycled the key all the way off and then restarted it.

 

[SHOZ123]

Rather than **** around with it for the rest of the year I would suggest buying four new coils. Put the new ones in the back then you can play guess the coil the easy way with the fronts and your four extra coils.

 

[mustangracer91]

Only thing is that the exact symptoms/stalling/cycle the key, etc... has coils written all over it. Next time it stalls, try starting it without turning the key off. When my coils were going, it would not start unless you cycled the key all the way off and then restarted it.

I'm not trying to be arguementative, but that's not necessarily the case, it all depends on the how the egr is controlled...like I stated earlier, I'm not familiar with how the egr is controlled on those motors, but if it's an electronically controlled egr, part of your key cycling is it goes through a full sweep of motion on the egr valve, and alot of times it's just a small chunk of carbon, plugging up the small hole left from years of carboning up, and with no exhaust pressure trying to push the carbon through the hole, the valve will close and the vehicle will start and run correctly until the valve opens again, and you come to a stop... it's just a lesson I learned the hard way...

 

[bacernate]

This engine has a real problem with very wet gooey carbon not hard chunks that can hold a egr open.
Bottom line the coils will skew the maf sensor signal and cause all sorts of running and stalling problems.
Fwiw it's just a regular vacuum controlled egr not one of those electronic piles gm uses.

 

[JoesSHO]

I'm not trying to be argumentative either- It's just that the dozens of SHO's I've looked at with bad coils, do this exact thing. While it could be an EGR, I've never seen one do it. But hey- thoughts are good, one more thing to test.

You can bench test them, but it's getting to be time to replace them anyway. If you're going to keep the car, change them as bacernate said- they'll mess up all sorts of stuff when going bad.

Paul's right- buy 4 new coils if you're going to keep the car. When coils go, they go consecutively and in somewhat short order. You'll drive yourself nuts chasing it down. If you want to clean the EGR or buy a new one or whatever first, you could try that too, but I'm betting on coils.

 

[Mr Anonymous]

I'm not trying to be arguementative, but that's not necessarily the case, it all depends on the how the egr is controlled...like I stated earlier, I'm not familiar with how the egr is controlled on those motors, but if it's an electronically controlled egr, part of your key cycling is it goes through a full sweep of motion on the egr valve, and alot of times it's just a small chunk of carbon, plugging up the small hole left from years of carboning up, and with no exhaust pressure trying to push the carbon through the hole, the valve will close and the vehicle will start and run correctly until the valve opens again, and you come to a stop... it's just a lesson I learned the hard way...

It's a coil problem.

A. The EGR is vacuum controlled.
B. If an EGR valve fails it fails closed.
C. V8 SHO EGR valves never fail.
D. 99.9% of misfire and stalling problems with these cars are coil related.

 

[JoesSHO]