My car is on Speed Density with cams, HKS gtII turbo, all upgraded piping, 1250cc injectors, 255 walboro, and 91 pump gas.

I went to the track last month and the car ran perfectly through out the day. However, when it was time to head home, the car wouldn't start. I gave it several tries but no luck. I let it sit for about 30 minutes and it fired up. I left for home (4hr drive). Within the first 10 minutes on the freeway, the car would spike lean (21 afr according to my zeitronix) while cruising. It would nearly die but the motor seem to catch itself and recover with throttle input.

After an hour or 2 of driving, the car would actually go lean and stall out while at speed, a couple times at 80mph. Super scary trying to get from the outside lanes with no power steering and dead motor to the emergency lane. I pulled over multiple times on the freeway and tried to crank it but nothing. After 5 -15 min of letting it cool and cranking every now and then it would start. This happened several times.

Once I hit traffic closer to home it got worse. It would die if I let it coast or let my RPMs get below 4k. So I was stalling left and right every time the car in front would slow down. Had to do the same as before and keep cranking it for 5-10 minutes before it would start.

I finally gave up and pulled into a parking garage half way home and I let the car sit for 1hr. After that it started right up like always and didn't stall at all on my way home.

Today some of the symptoms came back. I was cruising on the freeway with the AC on at about 75mph and the car's AFR spiked to 21 and almost stalled. Happened about 5 times then went away.

Sorry for the long story but I figured more details the better.

What could be causing this? Is it an issue with my tune or something mechanical.

TIA

 

bump, any help would be appreciated.

 

i am having this exact same issue....
very similar mods.
any ideas?

 

fuel pump getting hot and breaking down and start to work when it cool down

 

i have a fuel pressure gauge in the car.
fuel pressure never drops below 42 psi when idling

if you get it "past" this issue, and warmed up, you can make pulls and the fuel pressure is good.