Guys, coming here for some advice on this issue that began yesterday afternoon. I'll give the back story and then the symptoms and what I've done for diagnostic/chain of events testing.
A year or so ago, my fuel pump resistor went bad. I pulled the relay under the hood and bent one of the prongs (as seen in an online article, some people also jumper 2 of the terminals with a paperclip and remove the relay entirely), reinserted it, and the car started and ran fine for over a year until yesterday. I had driven to work 25 miles in the morning, and drove the 25 miles back home at 5pm. It was about 82*, the first hot day of the year. This may or not have anything to do with the problem but I thought I'd include it as temp changes of >40* can change things slightly when talking in terms of heat soak etc.
Anyway, I stopped at my brothers house after getting back to town, shut off the car, stayed for less than 10 minutes and walked out, started the car, drove off about 600 feet and the car started bucking and jerking like when your battery is almost dead and your alternator isn't charging it so you're basically on battery alone, i.e. you're not getting enough energy to fire the plugs correctly. I pulled into a parking lot and the Idle air control valve either opened or closed (not sure which way) and there was an immense sucking noise coming from under the hood. I shut the car down, tried to restart it, it just cranked over, but would not fire. I let it sit for a few minutes while on the phone calling for a ride, probably 2-3 minutes, and I cranked it again, it started and ran for a few seconds before starting to buck again. After about a minute of playing with the throttle I shut it down. After I shut it off I pulled the ECM fuse, reinserted it and it started, and ran smooth so I put it in gear and set back out for home when about 100 feet away it started to lose power again and the engine began bucking and sputtering. I pulled into another parking lot, and shut it off and called AAA for a tow, 6 blocks from home...
They finally show up about an hour later so I jump in, start the car and it runs perfectly fine, Put it in gear, the tow truck guy offers to follow me home but I decide it'd be better to load up the car in a parking lot than in the middle of a busy street. We get it back to the house, he sets it down in the middle of the road, I re-start it, drive it into the driveway and leave it running. 15 minutes later, just idling, it starts to spit and sputter and almost dies again. I find this odd because the car never flat out dies, it attempts to keep running even though the RPM's are at 400 or less ( buit not 0 like I read about for a Crank Position sensor). I remember back in my programming days for the Iroc that I could initiate any amount of "stall saver" parameters. So I assume this is whats kicking in, some stall saver mode. But the odd thing is that there have thus far been no SES lights.
I let it sit for 30 minutes and re-started it, let it run for 40 minutes and it never attempted to stall out, I shut it down and immediately tried to restart it. AGAIN, it just cranked and cranked, but would not fire. I checked the schraeder valve at the fuel rail to ensure that there was fuel in the rail under pressure, but I had no gauge to determine at what pressure it was in there. So I again removed the ECM fuse and got the car started on the 3rd attempt.
I have no flashing security light, no Resistor in my key (like on my camaro.. stupid VATS system anyway)
I have no SES light.
I have fuel and spark when the engine is cold.
I have a no-fire situation when the engine has been running.
ANY ideas are appreciated.
Thanks!
