Date registered: Feb 2005
Vehicle: '87 570SEC (FrankenBenz) '87 560SEL (Lisa), '87 560SEC (Bling)
Location: Las Vegas, NV
Mentioned: 2 Post(s)
Quoted: 165 Post(s)
Before you strip it, here's one more thing to try (and it's free - no parts). I had the same problem - car would start and idle fine, if you were lucky it would drive fine. If not, it would not take any gas. No power, stumble, stumble, then ALL THE POWER FINALLY COMES IN AT ONCE.
Turns out to have been a mixture adjustment that was on the edge of completely bad. This adjustment is made with a long 3mm allen wrench through the air cleaner. Put the allen wrench through the air cleaner hole and push down to engage the adjustment (it's spring loaded up). Once you've verified the allen is in the adjusting screw (try to turn it) then give it 1/2 turn clockwise. That's all it should need. My 560SEC went from FUBAR, to amazingly great - an idle that is so smooth you can't feel it and enough power to smoke the tires.
Turn the adjustment and start the car. You'll know if that fixed it immediately.
US '87 560SEC with Euro headlights, clear markers, H&Rs, 18x8.5, ATE slotted rotors with semi-metallics, BergWerks FGS, 3.07 Limited Slip.
In progress - FrankenBenz SEC: GM LS6 5.7L engine with custom 4L60E 4-spd overdrive transmission, GM rack and pinion.
One of my goals with the FrankenBenz is to scare women and children, and to have Lexus drivers spill their latte.