ptcfast2 Posted May 30, 2011 Author Report Share Posted May 30, 2011 (edited) sounds like too much load on the power system... most likely stemming from a poor connection, such as a loose ground or alt connection? check the alt's heavy wire, and make sure you properly attached the grounding strap for the engine... Alternatively, You could just have a weak alternator... I had the alternator and battery checked out last last weekend - all is good it seems. The alternator is only a few months old (and new!) so I'd be pretty sad if it was already messing up. Anyways, it seems the problem is coinciding with a sudden RPM drop on the tach. The drop seems to occur during the final downshift - after applying the brakes for a few seconds the lights will dim, air will stop coming out of the vents, and the RPM almost hits zero before bouncing back to around the normal idle RPM. The final downshift is also bit "clunkier" than normal as I assume it's happening at the wrong RPM. Once the engine bounces back the RPM reading is normal and stead until I repeat the procedure. The car managed to stall out when I was braking and turning into a parking lot last weekend - it started right back up. Note: From what I remember, my old engine used to have this problem, but it didn't cause the lights to dim or anything. I would see the tach randomly drop and bounce back sometimes when braking and the car seemed to be unaffected. I've ignored it (until now) as nothing actually happened besides a weird "bouncy" tachometer reading. It seems that the underlying problem is actually showing up with the new engine. I don't think it's the IAC sensor as the one on the TB presently is brand new (plus the car had the problem, although less severe, with the old sensor/engine). The only sensor on the air intake that is not new is the MAF sensor....my LG8 was a turn key GM crate so it came with *almost* everything. Edited May 30, 2011 by ptcfast2 Quote Link to comment Share on other sites More sharing options...
ptcfast2 Posted August 1, 2011 Author Report Share Posted August 1, 2011 (edited) If anyone happens to care or stumbles across this problem, the issue I had was EVAP related. Unplugging the sensor fixed the issue immediately, so made it a piece of cake to diagnose/fix. Oh, and I tore the old engine apart and found coolant all up in the oil pan. Didn't bother to see what actually caused the sudden internal leak (intake gaskets were relatively new and were looking perfect when I took the manifolds off). Oh well... Edited August 1, 2011 by ptcfast2 Quote Link to comment Share on other sites More sharing options...
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