I bought the car last Friday and have been trying to figure it out since then. I am mechanically inclined and I have money to fix it. To start out the car has aftermarket exhaust on it with no cat (NM doesn't have emissions) , a new water pump, dist cap, rotor and plug wires, fuel pump, FPR and a brand new o2 Sensor. Also the TPS is supposed to be brand new too, and it does look it.
When I start it up the car runs great, it will sit and idle no problem. when I go for a drive down the highway and come back to the house and leave it idling the car will start to surge after about a minute, and then after about a minute more it will die from it. It is an automatic. I can feather the gas to make it not do it but even then it still surges. It is worse under a load than in neutral, but will die in either one.
I drove the car to work the other day ( I work out of town so it was a 3 hour drive there on Sunday night and a three hour drive back here Friday after work) and I am going to do the same today. On the highway i have no problems at all. Just trying to see if this is a problem that has happened to anyone else. btw the engine only has 135,000 original miles on it. And all fluids are good. If I forgot any info please throw it in!

 

The egr valve might be opening at idle, it's not supposed to open at idle & will cause surging & stalling.

 

lmao yup Ex-x-fire........... you hit the nail on the head. Ive been through this also. Same 3.1 v6...... My Egr valve is 2 years old and it started doing this again so i made a block off plate. and now the damn SES light comes on all the time. But its better than that Surging bucking BS................................ Might also want to check the Fuel pressure. Because..

New stands for: Never Ever Worked.........

So check that Fuel pressure also. What i did when i check my EGR.... Im a b tech so ive got stuff. but i took a rubber cone blocked the Intake port started the car, and felt the flex pipe for any flow.. couldnt feel it. but heard it and smelled it..... blocked the tail pipes for a second and WOW the air was pouring out of the EGR to the intake port.................... so maybe you can figure out a way to do that.....

Multec Fuel injectors on our cars...... They are not liking the ethanol and that can probably be debated. however they arent too too expensive like 50 bucks a piece. i did all of mine glad to own a V6 that day!!!! haha

 

Thank you both! I'll see about testing it and working on some type of block off after work today. I drove the car two hundred miles yesterday and it did fine except when I stopped. If I can't do that I'll probably just see about finding another valve.
As far as injectors go that will definately be something I look at. I wouldn't mind spending some money to get some drivability and power out of it. I'm used to driving my 94 4wd chevy truck all cam'd out, so unless mods are going to cut my fuel mileage in half that's not an issue, it's so cheap to drive a car! Thank you guys, I'm open to any info

 

HAHA yea, i used to drive a 1990 Chevy k1500. 355 2.02/1.6valves 1.6 rockers Comp 268 cam.... it was some wicked!!!! but she liked the fuel. so i bought my 1991 Camaro rs 3.1. getting a tad more than double the MPG!!!!!!! Its been easy on my wallet. and ive grown on it quite a bit. I love it.

Dont Expect a huge diffrence in HP with new injectors, unless yours are really bad. I didnt gain much if any thing at all... Just The "Starts up every time" lol But now I think im going to change the FPR, i dont know if its ever been changed. im at 215K miles. I take care of it, fix/replace things before they go bad if i can help it.

 

I know this thread is kinda old but I have an update. The car has still been doing the whole surging deal but not as much since it had gotten quite a bit colder the last month. As before I can start the car and it will start up just fine and idle., but after being driven it will die at an idle and smell really rich . Today I made a block off plate for the EGR. It was alot simpler than I was thinking I just hadn't had time lately. So I did that and the now the rich smell has gone away but it still surges.. Any ideas would help!

 

So I think I found my problem, to anyone this may help! The car started to have a more erotic idle the last couple weeks. First I blocked off the EGR, the gasket was sick, nearly all the way plugged up with ****.. Anyway after this it didn't seem to help, still wasn't throwing any codes at all though. I accidently left the metal hose coming from the egr pointed at the top of the intake and after two days there was all kinds of black stuff sprayed on the intake. So that got me to thinking, after years of putting that nasty **** into the intake I bet the intake is pretty dirty so after a couple days I got some carb cleaner and a roll of paper towels and took the air cleaner tube off. I continued to turn the inside from completely black to shiny silver metal. It was filthy. Put a bottle of seafoam in it and it seems to be running better. But it still has a bit of an Iratic idle and will die eventually when just sitting there. I changed the fuel filter during all this too. So now that I cleaned the intake out I started throwing codes.
A code 32 - because of the EGR,
And A code 35- because of an idle air control problem.
I plan on taking the IAC out and clean it out again-( I already have once) and then see if the code clears after I reset it. If not then I will buy a new IAC for 49$ from auto zone in town and see if that fixed my crazy idle. I'm just glad to be get ting somewhere (:[ATTACH][/ATTACH]

 

UPDATE

I replaced the idle air control IAC valve and it didn't fix my problem. The car runs great on the highway still but still has the Iratic idle. When started up it purrs.. Then After idling for about a minute or two the car will start to sound like it has a miss. If I hold the gas down even just a little bit at 1500or so it goes away and purrs again. It is worse if you go drive it and then let it idle, particularly waiting in line at Mcdonalds or something! I replaced the coolant temp sensor with the yellow and black wire. Nothing has seemed to make a difference. Getting kinda tired of chasing it but I'm ready to sell it and get a welding truck and I can't get any money out of it if it dies idling after a test drive.. Thinking injectors might be next. I just wanted to keep posting progress, because I know I'm not the only one with this problem and I'm gonna keep dumping money into it until I fix it lol

One more thing I doubt has anything to do with it but my fan never turns on except for when I put the paper clip in to flash codes. Checked the fuse and it was good so I figure it's gotta be the relay just haven't got around to testing it.

 

I guess you could do a compression test to see if everything is even there.
You can send out the injectors to be cleaned/tested, you might find vacuum leaks as you take it apart.

 

I'll see about doing a compression test. I think that the internals are sound because of how good it runs when I first start it. It will idle for 30 minutes if it has just been sitting that's the part that gets me it seems like its something simple, this car is still my daily driver and I don't have any problems with it dying then usually because I never let it idle except for in the morning ( for 15 minutes every time ) and in the morning it idles fine because I haven't driven it.
I'll get there eventually

 

I'll see about doing a compression test. I think that the internals are sound because of how good it runs when I first start it. It will idle for 30 minutes if it has just been sitting that's the part that gets me it seems like its something simple, this car is still my daily driver and I don't have any problems with it dying then usually because I never let it idle except for in the morning ( for 15 minutes every time ) and in the morning it idles fine because I haven't driven it.
I'll get there eventually
The coil they have on there is not mounted correctly because the old one is still there. It is wired in and I have checked it seems to be done correctly, it's not that hard I put the blaster coil on my k1500 last year pretty effortlessly. Mine was just mounted better. Off to work I go

 

unhook the battery for 30 seconds or so reconnect it and do the idle relearn procedure .

seafoaming the engine also wouldnt hurt , will help get all that built up carbon out of it

 

will do both I run 91 octane in it.. And fuel additive regularly just haven't done it in a couple weeks. I did the idle relearn after I did the IAC but forgot to disconnect the battery before starting.

On these cars I noticed that when you disconnect the battery if you don't go turn the key forward the system never discharges. Just thought that was interesting not that there is anything wrong with it.