What would be the cause of rough idle and dying on a 1987 gmc truck?

Question

350 with throttle body injection. Idles rough and dies. Straightens out after warm.

Answer 1

Check your battery, it may need to be replaced. And yes, a bad battery will/can make a motor run like crap. Also, check to see if all spark wires/coil wire is not compromised or coming into contact with something.

Answer 2

Go to your nearby parts store and get a Haynes manual. 87 is the 1st year GM put fuel injection in their trucks, and there is a computer. The book will show you exactly how to pull the code from the computer, and what it means. The only tool you need to find the code is a paperclip, or a short piece of wire. The book will also give you some basic troubleshooting guidelines.
I'm thinking it is the EGR system.

Answer 3

My brother says the following:

It's the fuel injection system period. Don't look for anything else. No maf sensor because your truck doesn't even have one. The O2 sensor, the truck should run even if it doesn't have one. Mainly look at the throttle injections. Check the injector and the electrical connectors. That's your problem.

Answer 4

1987 is the key here 350 id first check the egr valve seeing its only bad when cold chances r its not working proper im a mechanic by trade

Answer 5

could be electronic choke. also I had 1 that was the coolant temp sensor. It controls the mixture of fuel and air at certain temps.

Answer 6

have a tech scan the system looking at ect sensor if its not reading the correct coolant temp it will affect cold operatioin.also ck timing

Answer 7

You said it. The problem is that it's GM!

Answer 8

look at O2 sensor, and MAF if it has one