Howdy, picked up this 87 a while back, 305 tpi auto, who knows how many miles.
While driving, it runs fine, minus my tranny having Parkinson's.
When stopped in gear, it'll idle nice for a bit, then after sitting for a minute it'll start hunting 100-400rpm rapidly and trying to die, then it'll stop, or if I 2 foot it/blip the throttle when it tries, then it'll stay happy.
No codes, MAF is intact, new maf and burn off relays.
Didn't do this when I got it, started after I deleted the air box and put in a k&n cone filter. I put flex tube where the air box was, and sealed the edges with silicon caulking/permatex and heat shrunk duct tape. Can't feel any leaks there, spraying carb cleaner around the connections doesn't change anything, so I don't think that's leaking.

Cleaned my IAC and reset my tps. Only does it in gear when stopped for a minute or two, I can stop for a little and it'll stay at 650.

 

MAF cars do not like it when you do the K&N cone filter thing to them. it probably only started doing this when you made that mod, right? put it back the way its supposed to be.

 

Correct, I just figured I had an air leak between the maf and TB. The old air filter housing is..currently FUBAR, courtesy of the worlds most versatile wrench haha. Short of a re-tune, any way of making the Maf play nice with the new filter?

 

no, not really. buy yourself a factory stock air cleaner assembly. and throw away that cone filter. just one of the reasons youre having problems. the K&N has to be oiled, and the oil WILL contaminate the MAF. and a new (NOT re-man) MAF is several hundred dollars.

 

Looks like its speed density or carb time then

 

well, that's your call. you can make a MAF system work, you just need to treat it right.

 

That seems like a lot of trouble to go through just to be able to run a K&N filter.

 

my thoughts exactly, but a lot of people, get all wrapped up in what LOOKS cool. instead of what WORKS cool.this dude must like the "bling" factor very much.

 

Or, people do a mod because an old part was broken, then it turns out to have a negative side effect.
But, swap back the old part! Oh yeah, it was broken!
My ta is lifted. With mud tires, and half assed welds. There is zero "bling".
If simply putting on a cone filter will make the electric unhappy, then its time for a new system.