question about rpm drops and flat spots in power/torque...

Ok, i got a question for anyone who knows the answer

when the celica's a little cold the throttle is noticeably hesitant... then once its warmed up, the rpm drops only when im revving it at a certain rpm (2000rpm)... i hold the throttle down ever so slightly until it reaches 2000rpm, then as soon as it does, without my foot moving at all, it will drop down to about 1000rpm then slowly move back up and repeat this process untill i either take my foot off the throttle or give her more throttle... hope that makes sense ?!?

its starting to worry me a little bit ! it happens sometimes at idle too, so say it idles at 1000rpm, after shes warmed up, i come to a stop then the revs drop maybe 200rpm and then build back up and drop again until i give it some throttle....

its strange and i've never seen anything like it before!

there are also a few flat spots in the power band before tvis kicks in... it feels like someones holding it back then letting go, then holding back, then letting go... not massively noticeable, but enough to get me a little worried....

i have a sneaking suspicion that its running a little lean or the timings been fiddled with... the guy before me had a piggy-back "power-chip' on it so could this be the problem?

any help would be great thanks guys!

 

i think it has something to do with a sensor needing replacement... the sensor that tells the injectors to turn off at 2000rpm when decelerating? that would explain why it drops back down to the idle rpm then the injectors would turn back on until it hits the 2000rpm... thats just a guess tho!

 

its been happening a while and i've filled the coolant a few times (not that it needed it - wasnt low) and i've also done a service on it...

what ekse could it be...? its had a new rad and rad cap just before i got it, maybe half a yr ago...

 

cheers guys, stil working on it but i did clean the TB out only a few months back... ill give it another go tho! ill keep ya posted

cheers again!