Electrical Normal Tps Operation ?

BlackBaer5.0

Member
Nov 26, 2003
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I have been going thru the Surging idle checklist to troubleshoot a stalling idle problem and came up with a couple questions

First the problem; after the car is warmed up, and I slow down to a stop , the rpms slightly fluctuate ( not more than 200 in either direction) recover, then lope a bit, and stall out.

My question; While setting base idle and checking voltage on the TPS, I noted that while probing the grn and black wiring.As I sweep the throttle, the voltage would climb from .99v and up while I moved the plate. When I get past about 1/3 the way open ( approx ~2.5v) it becomes an open circuit until I get past approx 3/4 open,then the voltage comes back ( approx 3.4-3.8) and climbs all the way up to full open (approx 4.6-4.8v)

Is the open circuit ( no voltage value) between ~1/3 to ~3/4 throttle normal operation for this tps?
I tried another I had laying around and nearly the same thing.

I am inclined to think it is NOT. But two doing the same thing? what the heck?

BTW, I am not seeing any codes,
I have fixed all the vacuum leaks I can find, even a doosie in the brake booter I replaced, All the grounds mentioned in the checklist have been verified, or re-terminated.
The speed sensor in the trans is new, as well as both o2 sensors, and the injector engine wire looms are new ( NOS)
Other then stalling out when warm, It runs well, just missing some power around 2800-3800




91 fox 5.0 stock block/ AFR 160 heads, ford e-cam , manual 5 speed, Cobra upper/lower intake, 24# injectors, with matched and clocked C&n MAF that is taking air from the wheel well. ( clocking the maf made quite a difference ), and all emission related parts were lost :)
timing , is 13deg spout out, 93oct gas , FPSI is 32#'s

thanks for any help,
 
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After reading a couple more pages of search results, on " stalling "
My car did come with cruise control, which has since been removed. ( the section that controls the throttle and accuator)
the part that is in the trans is still there and hooked up.

Possibility? But like I said, no VSS codes to be found .

thanks again