Loping under light load
 

I have noticed that my N/A Supra seems to lope under light load. Curious as to any easy diagnostics or remedies? Under some acceleration it is not there just when you are trying to cruise along with minor throttle.

Any ideas? Could this be caused by overheating or air in the cooling cause I have not bled the system and my overfill bottle had not been filled yet? It's full now though, the cooling system filled it and then I had to add more coolant to the radiator. I might have air still in the cooling system. The car has not overheated according to my temp guage. As it is not tagged yet I have only snuck the car out a few times up here on the mountain for 20 minute test drives. I am going to park it facing up a hill and see if I can get it to burp up the last air with the cap off.. Any comments? Don't think I have a BHG cause the oil looked normal when I did the oil change, No accumulation or milky film under the oil cap. the cylinders all read the same or close compression, I am getting no white smoke from the exhaust, the plugs looked good and tan on removal. Thanks, Scott

if the car is filling the overfill on its own then it got hot or your radiator cap is too weak..
as for the lope, it takes alot to get a noticable lope out of these cars when i first got mine both of my cams were off by a tooth advanced on the intake retarded on the exhaust and it loped but not too much its gonna be a fuel or ignition problem check your fuel pressure with and without the regulator it should raise about 10 psi +- a little without the regulator hooked up check your timing under light load just give it a little throttle and see where it goes it might be your wires sounds like what your getting is a miss not a lope but idk... is it more of a shake? my car shakes at 2k just about every gear doesnt matter with throttle or anything but it is more noticable at cruising or light throttle and nothing is actually wrong with it it just does it ...

Loping or surging under light load
 

I called a friend of mine and he said it could be dirty injectors. I am unsure if I should call it surging or loping. It's like when you are going it starts to rock you forward and back like it surges and then lets go on a very rythmic basis. Not there in hard acceleration or gear downs just as you are under light to medium load. Seems to get worse as the car warms up.

I sucked a lot of stuff through the throttle body cause of a rats nest in the air cleaner. When it happens it rocks you like your in a rocker forward and back it's annoying as hell. Its not so much a miss as like you are pushing on the gas lightly and then off and then on and then off about once every half second. My cams are dead on cause I just did the timing belt.

Where is the fuel regulator you speak of? Thanks, Scott

Have you checked for codes yet? Keep in mind that not all codes will cause the CEL to stay on. To me it almost sounds like a bad connection to the TPS (which 2 of my 3 supra's have had thanks to the lack of that metal clip on the electrical connector). Anyway, check the codes!

Metal CLip????
 

Neither of my Supras have metal clips on the TPS connector. Here is a pic of what I have. I suppose I can get this clip from the Dealer if it is missing? Or is it inside the connector? I see something metal there. Thanks, Scott

The metal clip (it looks like a paperclip) goes on the outside of the TPS connector. There's a little groove cut in the connector towards the end of it (furthest from the wires) that is slips onto, which helps lock it in place on the TPS. Without it, the connector can vibrate loose giving the ECU intermittent readings from the TPS.

TPS clip
 

Well I guess I need o get a couple of those. One for each car. Obviously I am missing that clip on both cars if it isn't showing in that pic. I'll stop at the dealer tomorrow and see if they are available. Thanks!

That plug is attached to the wiring harness. So without buying a whole harness, you probably can't get the plug. The best place is probably the junk yard for parts like that. Good luck getting just the clips. On my car I have a few plugs that are broken but never fall off.

Hmmm
 

Well my plug is fine all I need is the clip. Can anyone post a pic of the connector with the clip on? Thanks, Scott

i just zip tied mine it stays on perfectly has never came loose it could be dirty injectors i doubt its your tps mine does the same thing but only at 2k-2200 2300 and what your describing is a surge check your o2 it might be reading strange giving you a rich/lean condition and check your air flow meter it could also cause this both can happen without throwing codes also because there working within parameters just not at the right time i noticed that my surge became alot less noticable when i unplugged my idle air control