Rough running 87 GN. Please help

[MarkieMark]

My 87 Grand National started running a little funny today. If you get on it and floor it for a couple seconds it runs fine but then as you slow down and start to drive normal again it doesnt seem to want to run at all. Itll sputter when you give it gas and try to die like its overloading with fuel. If you drive the car normal though it will run fine the whole time. A buddy said it could possibly be the ignition module? Any help would be appreciated thanks

 

[blackgn1]

Got any Scanmaster readings? If you don't have one.....get one? Flooring the car when it's not running correctly sounds destuctive to me. Knock! Knock! "who's there?" Headgasket......Headgastket who????

 

[MarkieMark]

Got any Scanmaster readings? If you don't have one.....get one? Flooring the car when it's not running correctly sounds destuctive to me. Knock! Knock! "who's there?" Headgasket......Headgastket who????

It was running fine before I floored it. No I dont have a scanmaster.

 

[TurboBuRick]

It was running fine before I floored it. No I dont have a scanmaster.

Most likley blew off some vacuum line or a intercooler coupling. Get under the hood and have as look around.

 

[MarkieMark]

What gets me is it will run fine after it idles for a while and clears out. It runs fine if you drive it normal or if you get on it but after you get on it it starts running funny like its flooding out but if you let it run for a while it does it all over again

 

[Phoneguy]

You need to address this problem before you go out and floor-it again.
As was posted above check your vaccum lines and intercooler couplers.
List the mods done to the car, get a scanmaster or some kind of logger, get a fuel pressure guage so that you can monitor your pressure and give us some kind of assistance to help you.

Read, read, read and read some more. We can help you but we need info to do this.

Welcome aboard.

Bryan

 

[MarkieMark]

Its stock with a adjustable fuel pressure regulator. Im pretty sure though the guy I got it from didnt check the fuel pressure when he put it on though. I will check all vacuums and the fuel pressure

 

[Just a Six??]

You also need to see Fuel pressure when the car is boosting to see if it rises 1-1 for the boost. Gotta get a 3ft hose & tape it to the windshield. Also what chip is in it as some use different FP starting points.

 

[MarkieMark]

You also need to see Fuel pressure when the car is boosting to see if it rises 1-1 for the boost. Gotta get a 3ft hose & tape it to the windshield. Also what chip is in it as some use different FP starting points.

Its just stock no chip. Where should the fp be?

 

[blackgn1]

Have you got a boost gauge. You really need to know whats going on with the car. Boost, fuel pressure, TPS setting, IAC setting, ect. Scanmaster can get everything in check.

 

[MarkieMark]

Have you got a boost gauge. You really need to know whats going on with the car. Boost, fuel pressure, TPS setting, IAC setting, ect. Scanmaster can get everything in check.

I got a gauge a boost gauge but have to put it on. I just got the car a week ago

 

[blackgn1]

We need to know what kind of boost your running. It could be 10psi. Could be +20psi. Just be careful till you know for sure. Right now you can't monitor knock.

 

[87spools]

lots of things could be wrong! hell could even be a fuel filter! listen to what everyone is saying and check vaccuum lines. thats a good start. if your coils were bad it would misfire under boost due to not enough spark energy. if ignition control module is bad would also misfire under boost. its prob vaccuum issue or egr or tps. scanmaster will save you time and money now and in the future. as well as a knock gage.