I recently purchased a 70' with a 87 L98 engine installed. The guy I bought it from had just finished the installation of the engine when I bought it. The motor appeared to run fine with no problems.
A few days later the motor started surging a bit at low rmps especially leaving from a stop sign. It wasnt bad, and I could accelerate through it. My thought was the injectors were prob. a bit dirty so I went to the autoparts store and picked up a bottle of Chevron fuel injector cleaner. I drove the car around for about 45 minutes with no problems. Later that night I took the family out to dinner in the malibu (the restraunt was about an hour away) and just when I pulled in to the place the car died! I waited about a minute and restarted the car, it started ok but then seemed to loose fuel pressure. When I stepped on the gas the car would just stumble and not accelerate.
Ok.. I figured that the cleaner just got a bunch of gunk loose and cloged the fuel filter.. no biggie.. After eating dinner the car started up and made it home (barely) but then died 1 block from the house. We walked home and I went and got the car an hour later. So yesterday I changed the fuel filter, the old one was full of junk. I figured Id solved my problem. After changing the filter I let the car idle for about 90 minutes out in the driveway and low and behold the same problem. The car seems like it loosing fuel pressure. You can tell its starting by the surging, it seems starved for fuel and then seems to get a bit more fuel, the rpms jump up a bit. When I try to give it a little gas sometime I can pull it out of its 'starvation' and get the engine stable again, but eventually it will die. The car will not restart imediatly after this happens but if I let it sit for 5 mins or so it will restart and the problem usually reoccurs after 10 mins or so.
So, Im not sure what the problem is.. there appears to be 3 issues that I can identify:
1. The injector cleaner is screwing something up somehow. Could the filter be cloged again?
2. Something wrong with the fuel pump that causes it to die after 90 mins or so of operation even though I can hear it running.
3. Heat, perhaps the gas is perculating (sp)? Ive driven the car longer in traffic for 2 hours before with no problem.
So Im not sure whats going on.. Id hate to drive the car to the local chevy dealership and pay 100$/hr to have them diagnose the prob..
Anyone have any suggestions at all?