I love this 84 GSL except for this problem which is making me crazy! Starts well cold, drive locally up to 3rd gear with no problems, grab coffee, etc. then hit the freeway. Stand on it. 4th...5th...suddenly feels like fuel starvation, no power, loses speed, rush hour traffic honking, pull over & fume(me). Replaced fuel pump, new filters,seemed fixed.

Weather got colder, problem came back. Colder the weather, more noticable the condition. Checked choke, replaced plugs, wires, rotor, swapped coils (from my other 7 project). Better until this morning, managed to nurse it to where I had to go & back but had to stay under 3500 rpm in 4th or it will die. 5th kills it. The clincher is that after 45 minutes it seems to be fine until the next freeway run from cold. Any advice greatly appreciated!

 

Judging by your location, I'd investigate carb icing. Rust in the gas tank clogging up your new filter would come second.

 

45 minutes is a long time to have your carb iced up, especially if it you have a Mazda "heated" manifold. I'm assuming you used a stock filter when you replaced it? If you did, take it off, throw it away and replace it with a much larger capacity unit. Something off a Rustang or equivalent.

 

I read that as after 45 minutes of sitting, you come out and jump in the car and it runs fine.

Rxcetera can't respond again. He really likes the way his name looks with 666 under it, and the minute he replies it changes on all his posts.

 

Actually Dyno, it's 45 minutes of running, sometimes the greater portion of that on the side of the freeway.

 

Just to make sure, check the float bowl windows (front and back) and make sure they are halfway full of fuel while running.
hanman

 

are u getting enough exhaust out, i had a clog on a car once that had those symtems, they told me it was the transmission,,,lol

 

Hey, it's fixed! Thank you all for your input. I went through all the suggestions, took off the fuel filter & checked for rust, etc. A little there but not enough to starve the f/p. As I lay there looking up at the check & cut valve wondering if it could be plugged I noticed what seemed to be a restrictive bend in the hose from the valve to the filter. Compared the hose to the other 7 project car.....different hose! Re-routed hose & eased the bend out, checked fuel volume, much increased, road test, & problem solved. At some point someone must have said "this hose should do." I'm still not sure why the 40 minute part but happy now!
Thanks again.

 

great job, seems like its always smaller than the problem was when its found..........