Last night I put an FRPP 70mm throttle body on my car (got it for free so cant complain). The car will idle fine, but when the engine speed is slowing down, like after a rev, or throwing it neutral when coming up to a light or stop sign, the engine speed sticks at 1200rpm, then drop to normal once the car is just about stopped. Could my TPS need adjusting, or is it something else?

 

Normal. Do a search on hanging RPM's. Also, did you unplug the battery for 5-10 after the install to reset the KAM?

 

The same exact thing happened to me when I installed an Accufab 70 mm TB. I searched the net and forums for ways to adjust it and found that if you have a volt meter you can test and adjust the TPS. I installed a new TPS ($51.00) and it made no difference with the hanging rpm's. After driving the car daily, the computer evenually self-adjusted after about a week or two, returning to proper idle. Be careful while driving with the hanging r's. Don't tailgate until it adjusts because when you take your foot off the gas pedal, it won't slow down!!!!

 

The TPS on EEC-V systems is not adustable, though the earlier EEC-IV units were.

On EEC-V (eek-5) the PCM continuously reads the TPS voltage and saves the lowest value observed as indication closeed throttle. This is called a "ratch" (reverse latch) value and is used as the basis for all subsequent TPS interpretations.

 

Just to post a little update. The hanging RPMs issue pretty much went away. Still does it a little but it is almost back to how it was. Ill give it a few more days.

 

It is normal for the engine to remain at 1000 rpm or so until the car completely stops--this is to ensure (or perhaps make damned sure) there is adequate hydraulic pressure for the hydroboost brakes...

 

o wow. learn something new every day. i had wondered why my car did that. even more noticable after the dyno. good info.