Forgive me if this has been posted before but I searched and couldn't find anything.

I have an 85 gsl-se that has 224000kms on it and sat for 3 years before I picked it up and put in new injectors (slightly oversize at 670cc I believe). At first the car ran good...but once the gas got down to 1/4 tank it started hesitating...every shift it would go good but after a few seconds of accelerating it had no power. If I'm driving around in a parking lot in first it will surge really badly.

The fuel filter has been replaced before I started it and I've run a can of seafoam through the tank. It seems to idle good around 800rpm once warmed up.

Any ideas would be muchly appreciated.

Thanks

 

When get a car that has been setting for several years I remove the fuel tank and clean it. They almost always need it. That's a long time for a fuel pump to set unused also.

You can make sure the tank is less than 1/2 full. Remove the rear left wheel and the plastic panel behind it. Remove the six small phillips screws and the fuel level sending unit. Now you can see inside the tank. I'm guessing you will find nasty stuff at the bottom of the tank. You might try draining the tank and rinse it with fresh gas, but that probably won't do it. There is a drain plug in the bottom.

 

That sounds like airflow to me - have you checked or changed your air filter recently? If you get a lot of crud in the filter it will restrict the engine at higher RPM's where you'll notice it most. Also, when the engine really gets spooling under acceleration, that's when your '6'-ports come open, and if you run out of air, you start to lose exhaust backpressure which keeps the ports open, causing a sudden drop-out of power; almost like a 'fluttering' under acceleration, for lack of a better term.

I would also suggest putting in a new cap and rotor, since they're cheap and seem to be the crux of a lot of 'loss of power' issues, especially when it starts to get cold out (they crack).

 

Air filter is new and spotless...to make things weirder it stopped doing it and pulled great today...then started doing it again...and then stopped again. Makes me think its gunk from the tank that is getting worked through the system. I'll run this tank through and change the fuel filter and then see how things go from there. If I can avoid dropping the tank I will..lol..I know....lazy. Taking her out tomorrow for a good run. We'll see what transpires.

Thanks for the tips guys.

If it doesn't clear up tomorrow I'll be dropping the tank as I think this is the most likely cause.

 

This is a long-shot, but years ago, I had a 'running on one rotor' (search that one...) issue which I traced down to the fuel injector pigtail for the #1 rotor intake path.

It was a weird cut-out kind of problem that only exhibited itself under certain random conditions. I figured it out by waiting for it to happen, popping the hood, and moving the wiring harness around. Sure enough, it ran great with the harness in one position, and started cutting-out with the harness pulled in another direction. Replaced the injector pigtails with Borg-Warner replacements ($7 ea x 2), and fixed it 100%.

Might try getting in there with it idling and pulling the various harnesses around and see what happens. You might be able to narrow it down, at least.

 

So I had it out today for a few hours. I noticed that it cut out at 4200rpm or so in every gear. It would pull strong up to about 4200rpm and then bog out as long as I was accelerating. If I was driving at a constant speed like at 3200 rpm it would seem to surge up and down a bit like it was choking off and then regaining itself. And then the last 10minutes of my drive on my way home it seemed to cure itself and pulled great all the way home...this time seeming to stumble occasionally just over 5000rpm. The stumbling seems to be more pronounced in lower gears than higher ones.

I think I've ruled out a fuel problem inasmuch as gunk getting into the lines. That injector problem sounds like it could be it though.

Thanks again.

 

Someone mentioned the 6-ports... maybe they are sticking open or patly open. You should be able to check their motion by pushing on them (when the engine is cold of course). You can replace the actuators with a second gen version, since they use a flex drive to move the actuators which keeps things from binding like the 1st gens have a potential to do.

I recall having an issue with the airflow meter ground, half way between the meter and the engine there's a wire splice from 1 wire to 3 - if one of those is breaking it'll run like crap. Kind of doubt that's what you're seeing but something to look at.

 

is your TPS set properly? plugged in?