Engine stalls after starting, now sluggish at WOT
Yesterday, I was in town, stopped for about 20 minutes and went to leave. It started, but was running like it was going to die, and after a minute it did. Then, after repeated attempts to start, nothing. Turned, but it wouldn't start. Didn't hear the fuel pump, so that was my first guess.
I get it towed home, and today I got a jump (battery ran down from attempted starting) and it started right away. It idles fine, even revs up like normal in park. Went for a test drive around the neighborhood, and it drives OK, but on an empty street, I floored it and it bogged down real bad. Didn't stall.
Repeatedly backing up and flooring it down the empty street, did the same, bogged down but didn't stall.
Cleaned the MAF, IAC, IAT and TPS. Temperature seems normal, PCV valve is good. No coolant leaks, sprayed cleaner around vacuum lines and gasket surfaces but there was no change in idle speed. Same thing, starts and idles fine but bogs down at wot.
Any ideas what it might be?
Edit: may have found it
Just for laughs, I unplugged the MAF and drove up and down the street. Aside from shifting hard into drive and reverse, no bogging down at wot.
1999 Alero GLS, 3400, 4T45E, current mods: WAI with Spectre HPR cone filter, VVME 55w 8000k HID kit
275,000 miles as of 05-14-2015 at 1559 est (3:59 pm)
Planned mods: F body front brake upgrade, ported UIM, LX9 top swap, ported exhaust mans, performance cam. Eventually, turbo or supercharger.
1999 Olds Bravada, 4300 Vortec v6, 4L60E. Current mods (on it when I bought it):
75mm ported throttle body, NGK stage 1 plugs, stage 1 heads.
Planned mods: injector upgrade, exhaust headers
Last edited by aleros_eat_rice : 12-13-2014 at 07:18 PM.