major hesitation

[ant33510]

When i get in my car ( 91' 240sx se, auto) in the morn and drive it it runs and performs like a dream, but once it has been runnin for like 15-25 min the performance goes to crap, i dunno why this is I live in fl so my driving conditions are pretty warm, i know that a colder engine performs better but i have never seen such an performance drop, I just did an tune up on my can ie. fuel filter, air filter, oil change, sparks and wires, and distributor cap w/ rotar. So i mena i would think that my car should run fairly well, can ne one give me some hints on what to do.
Thanx

[gh6o6]

i think its the fan clutch kicking in in the hot weather causing more resistance

[Arcane]

is it a hesitation when you press the accelarator or is your idle fluctuating???  if it's a hesitation, then you might want to check your fuel lines...also, have you cleaned your throttle body lately???  that could be it...  if it's an idle prob...check the faq's...

[ant33510]

i noticed tonight after wrk that my idle was indeed fluctuatin from 500 rpm and 1500 rpm, how do i clean the throttle? i have only had my car for a month so i have not done more than i thought was really nescssary for my car to run properly or something that could damage it.

[Alias]

Same problem here. Exactly the same. I was told to change the cap and rotor which make sno sense to me. Is they are bad it would always do it. Maybe an EGR problem?

[Alias]

BTW if its the fan clutch then you can here it running. Sounds kinda like a big fan blowing &nbsp;<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/hehe.gif" border="0" valign="absmiddle" alt=':hehe:'>