When I stop at a stop light, my engine rpms act funny. It’ll try to idle at 1500, then drop to 750 like it’s going to die, then go back up. It keeps doing this till i start moving again. The car doesn’t seem like it’s down on power, so i have no idea where to begin.
distributer??
well mine does the same, and mah car starts shaking like its a vibrator. oh yea, i have an auto
Did either of you fix this problem? I also have the same problem when idling at a light, etc.
Things I have tried and things I suspect:
I replaced:
plugs/wires/coil/ICM/rotor
O2 sensor
regrounded battery to frame with 0 awg wire
valve lash adjustment within the last 20k km.
cleaned the IAC, MAP, and throttle body intake
replaced the FITV
14.6 V with alt. engaged constantly (no charging problems suspected)
I tested the ripple of the rectifier diodes in the alternator’s regulator and found less than .5A of DC feedback (normal according to techs I spoke with).
I suspect perhaps that there’s a problem with either the IACV, TPS, or a temp/cooling sensor. I checked the CTS with a digital oscilloscope and the ramp seemed ok. Although, the ramp/frequency response of both the temp sensors should be the same and the one in the manifold dips first. I may replace these next.
I would very much like to continue dialogue on this as well as perhaps swap components with anyone with a '93 in the Toronto area (saves big bucks on parts this way sometimes).
If anyone wants to send me a dead TPS or MAP, please do. I’d really like to rip a few of these appart and reverse engineer them.
Those of you with problems, is your MAP voltage at closed throttle/resting idle at .46-.5V?? It should be.
Also check for even the smallest crack in the vac line going to the MAP sensor… this has known to cause problems.
Anyone is Toronto wanna get together and compare notes??
Andrew.