1984 GSL

• Runs fine under normal hiway load and city driving
• Idles fine, sounds fine under normal driving.
• Shakes and rattles under heavy load or high rpm acceleration. Especially on long, power-draining hills.
• Experience "diminishing returns" on hills. Behaves normally up to 1/2 throttle. After, the more i give, the slower I go. But I can wind it to redline slowly and it stays smooth.
• I swear I hear a metallic noise coming from the front cover, when I am really pushing it. it could be a loose heat shield though

Please tell me what you think is wrong with my car.

It started doing this last Saturday. I'm leaning toward a clogged cat, because I had similar problems once before but it cleared itself out. This time its much worse though.
I was 1 1/2 quarts low on oil today. I know, shoot me. I check it every time I fill up, but somehow mysteriously lost all that oil in a week. I run premix though as a safeguard against this sort of thing. Now the really odd thing is it seems to run much better now that I topped off the oil. Its still doing all the same things, just a less severely.
Could I have burnt up the oil pump chain or something? Could that be causing some sort of drag on the engine under load? Just speculating and hoping its not another popped engine.

I'm entertaining suggestions

 

I just drove down the block, you know what the cutting out thing reminds me of? The rev limiter on my FC. That might help describe it better.

 

Yeah, I shot ya! 1.5 qts low?!? Myyyy Gawwwwwd!!!!!
(Had enough? )

Uhhh, I answered honestly not because I think I know the answer, buit because I felt bad that you asked for help and only 15 people even bothered to look at this thread.

How are ytou with carbs? Is it possible that your secondaries are not working correctly? Crap built up on your linkage? They only open under load, such as going up hills, and a super lean engine sounds incredibly smooth!

Do a search and you'll find many posts on how to check the entire system that relates to opening them up.

 

any idea what kinda condition the clutch is in?

 

I would guess it's something to do with the secondaries as well.

 

I pulled the exhaust off this morning and drove around the block. wow-wee talk about loud, and I was flying. After I hit 3rd on a neighborhood street I was like hmmm not accelerating so fast then I looked down and realized I was doing almost 60 thats why...the car was backfiring and it looked like it was going to blow the hood off...what a difference straight exhaust will make...
I think its the converter! I'm going to clean up the carb though, check the linkage, check fuel pressure I guess.
I'm sure the secondaries are opening I can feel them around 3400 rpm. Thanks! I'll probably post again soon when something else breaks!

 

My $0.02. I too am disapointed in the lack of response, not nice guys!
BTW, this is the first I saw of your post.
3 guesses
Clogged cat
Sticking secondaries/linkage
accel pump (you said it would rev to redline smooth if you went slowly).

 

I'm not disappointed at all, I've gotten some great advice.
I have a cat replacement pipe on the way, we shall see if that fixes the problems. After taking the exhaust off, test running it, and putting it back on,...well the car won't idle right now. This car does strange things and needs alot of stuff worked out...thanks for the directions on where to start.

 

Are your plug wires hooked up properly???

 

wow 3 days and noone said fuel filter clogged

 

I've pretty much discounted a fuel delivery problem; I run two filters and changed them both out this summer, plus a visual inspection shows its still clean. . I could still be getting fuel starvation from running the two filters, but I've been doing that awhile and it hasn't been a problem.

I had a cracked hose to the anti afterburn thing and the tape on it melted, so thats why the idle was dropping off and also some of my performance loss, but it still is rough at higher RPM and WOT.. it ran really well with the exhaust disconnected, I mean lifting the front up shifting into 2nd which it never did before, I think the cats are shot so thats what I'm working on right now.
when I get time I'll check that I'm getting enough fuel and also I'm almost due for a tuneup new plugs wires oil and filter.