I have a 94 civic with a gsr swap thats having a strange issue.
So after driving my car for about an hr on the interstate it suddenly started acting funny. My A/F guage started bouncing between mid 14s and mid 15s. I kept going a little further and it started hesitating when id go to accelerate at all, so I pulled over and let it sit for 5 mins or so. I drove it around a little and it acted fine so i hopped back on the interstate and about a mile later it starts doing it again. I babied it to the next exit and right before the next exit it pegged lean on the gauge so I coasted off the exit. After letting it sit for about a half hr I decided to try it again, and it drove fine for the last hr of my trip.
It drove fine for the next few days while i kept an eye on it. I had to take another 2 hr trip back home and about an hr into it it started hesitating again so I pulled off and let it sit for 15 mins, then it drove the rest of the way home fine.

Any idea what could be wrong? I drive a lot of long distances and its never done this before. Could it be a weak fuel pump? Or the recent 100 degree temperatures? Any help would be appreciated.

 

sigh...
what ecu? was it tuned? bolt ons? any CELs? what injectors?
could be pump. its $20 to replace.
replace fuel filter too

 

Sorry, chipped p28. I/H/E/IM. Stock injectors. No check engine light, and the tune is stable. The fuel filter was replaced a few months ago.

I'm prepping the car for boost, so I just ordered a new Walboro fuel pump. It'll be here later this week. After some more digging, I think its a combination of the sudden heat, higher speed driving, and an old pump. I'll keep you updated if it doesn't fix it.