Dougs951S

Coming back to this issue again, but I made some observations today. The car seems like it is sometimes engaging the closed throttle switch on the tps, and sometimes not. This manifests its self by the car sometimes having a slightly high idle, and sometimes not engaging overrun fuel cut when I let off the throttle while in gear. In fact, the reason I am making this thread is because today I observed behavior I had never noticed it doing before. While out driving today, I was coasting in gear with the throttle closed, and watched on my economy gauge as the fuel cut in and out several times in a few seconds; which I assume is a strong indication of the idle contact switch closing and opening.

It clicks every time the throttle closes and its adjusted properly. New, stiffer return spring installed too. Do you guys all agree this is a sign of a failing contact switch and therefore a failing tps; before I take the filter and J boot off to replace the unit? I literally cant think of anything else that could cause the behaviour I observed today with the fuel cutting in and out while my foot was off the throttle and coasting down in gear from about 3200 rpm.

V2Rocket

Describe the fuel economy gauge's movement further, please.

In case you don't know the gauge is "2 in one"...it shows MPG while cruising but with closed idle switch and a particular very low RPM range (supposed to be idling while stopped, or very slow movement stop and go traffic basically) it shows fuel consumption in Gal/Hour...that's what the 0.5 and 1 on the gauge are for.

Dougs951S

This was at 2500+ rpm; it would quickly alternate between being pegged all the way to the far left (60+ mpg, or in other words fuel cut) and then 30ish mpg (car thinks im cruising, fuel not cut). Hy quickly I mean it bounced back and forth 3 or 4 times inna few seconds and I could feel each time the fuel would come back in because the car bucked a hair and I could hear the pop as fuel aas reintroduced.

V2Rocket

Well that is weird.
The little gauge is controlled by a combination of DME fuel injector pulsewidth and vehicle speed (the plug from the speedo that goes to the tach/MPG gauge).
So yeah...your DME isn't figuring idle all the way. Need an NA TPS? I should have a good used spare I'll send you for shipping.

thomasmryan

Back probe the dme idle validation wires with a shunted LED and see if it lights up.

A tad of slack in the throttle cable should help the micro switch engage.

Dougs951S

swapping the throttle body and tps to another unit I had on my shelf 100% fixed my issue, and really improved shift smoothness because I guess whatever was wrong with my old throttlebody was affecting AE and shifting, ect.