Mtobler2006

Hey everyone, im new to the site but i had to join so i can get input on my bizarre problem.
I Have a mostly stock 91 GT convertable with only an intake, exhaust, transmission and gears in it. It has 99000 miles on it, now heres my problem,After running the car for about 20 minutes, well beyond the time it takes to get to operating temp, all the sudden i lose all power above 3000 rpms, if i run it sooner above 3000, the problem occurs sooner. After that, the rpm at which i lose all power decreases untill eventually i cant even drive the car and it stalls out. Now heres the weird part, i turn off the car and wait even as little as a minute and start it back up and i can run fine for a little while and then the problem returns. After the problem starts, even in neutral i cant rev past a certain rpm, usaully it starts at 3300 and works its way down, in neutral and at wot! I can smell it running really rich when it when its holding rpm and it eventually just wont go untill i turn it off and on again. I have a couple codes, The are; One for the EGR valve not opening/not detected, Park Neutral Position Switch Circuit Open; A/C On -Manual (O), Manual Lever Position Sensor Out Of Range/A/C On (M,O), Clutch Switch Circuit Failure (M) I have a manual tranny by the way, from factory, not a swap.

Thats in KOEO, In KOER, i have;43 - o2 Sensors indicate lean at Full Throttle (M), 34 - EGR Valve Position/Pressure Feedback EGR Voltage Above Closed Limit (O,R), PFE or EVP circuit has intermittently failed above the closed limit of 0.67 volts (M)

Those are my codes, i have no idea what the cause is, i recently did plugs, wires, a coil, a maf, and i tried the wiggle tests, and unplugging sensors to see if it corrected the plroblem, the only sensors i havent disconnected are the baro, the map, and the o2's

Im at a loss here, please help

mjr46

I'd run a fuel pressure test for the lean condition to seee what pressure is at and tape gauge to windshiled and monitor so as to when prob occurs you can see what the pressure does ..if it drops off I'd suspect a weak pump or partially restricted fuel filter ....as for the egr prob..I'd make sure that the pintle is not partially stuck open which would be evident by a slightly rough idle.....but do the fuel pressure test first

sYckmYnded

i had SAME problem it was my fuel pump crapping out on me when it got hot, i replaced it with a BBK 190lph intank and havent had a problem since, took me 45mins to replace it

newpony

i have a 87 gt do you have to remove the tank to get to the fuel pump

Mtobler2006

you dont have to completely remove the tank, only unbolt the starps, and tilt the rear down and you can get to iy

silentvoice19

its a PITA droppin it just involves taken the straps off make sure your fuel filter it out of its bracket first, but anyways its simple bud put a jack and a peace of wood about the same length as the tank under it drop the straps and as its commin down undo the bracked holding the fuller pipe in spray aroudn it with alittle wd40 and give it alittle kick hahaha thats what i did and everything turned out fine. Ive had to drop my tank 4 times and ive gotten good at it give me 20 mins and i can have it out lol.