interesting engine routine...
 

when i speed up to 40 mph, then slow down. around 30 mph, the engine drops its rpms down to 900 and then rebounds them up to 1300, then drops downt o 900 and rebounds back to 1300, until i come to a complete stop (transmission is auto). what is the point of this little routine? or is there something wrong with my car :rolleyes:

btw. thanks to everyone who helped with my strut/leveling problem, the car looks and handles much better now that its all done!

Is your AC on when this happens? I have the same stuff at times with my AC on. It could be the auto trans downshifting too.
Im not sure but I guarantee one of these guys may know....

Good luck
Brock
86 Zermatt 951

thanks. nope AC isn't on. i thought it was downshifting too but i didn't feel any drag in the engine when it did this.

on a side note, a mechanic put "check lower right arm bushing". how many bushings are on the suspension? and are they hard to change? and should i do the change before an alignment?

bad tps

would the tps affect performance?

yep

how much and what performance? i.e. mid range, low end, torque, acceleration?

Naw, it's not important, it just tells the dme when you have your foot on the gas, and when it's floored, and when you have your foot off the gas.

I can't imagine that the dme not knowing that would make any significant difference in performance.

Try unplugging the TPS and see if the issue resolves itself. Then you'll have the culprit.

same thing happened to me... it was the screw/valve next to the throttle body that was too loose..

would the TPS affect gas mileage?

Yes, it would somewhat, but it simply sends the DME throttle-on, idle-on or full-throttle-enrichment signals. See George's note.

so in theory....if my TPS was really bad. i could have my foot off the gas, but the TPS telling my dme that im at full throttle and some extra gas would be burned (worst possible scenario probably not even plausible)

Well, the DME's gullible - it'll believe pretty much anything the sensors tell it. I doubt to the extreme in your example, but it could be confusing the DME.

do u think i should change it?? worht the 90 bux

If it isn't broke, then don't fix it. I think there is a routine in Clarks garage that tell you how to check it. If it checks good, then look for something else. Maybe what Eldorado suggested or the Idle control valve.