Posts: 677
Joined: 3/20/2006 From: Harleysville PA Status: offline
Ok, so my car is a 1988 GT, headers, o/r midpipe, flowmasters blah blah blah. Anyway, when i start the car when its cold or like first thing in the morning it will start up and idle good. When its warm and i start it, it will fire up the drop to about 500rpms then jump back up to around 1000 then back down to 500 it will do this about 3 or 4 times then it will idle good again. When idling then it will move around between 800 and 1000rpms. Also once in a while while driving the rpms will hang a little between shifts. What the problem, I just bought the car and am not familer with the 5.0 that much coming from a 4.6 SOHC. I was thinking IAC, so Im gonna clean that tommrow morning and see if that helps. Any other ideas?
_____________________________
I'm gettin' really good at barely gettin' by... 1998 GT - SOLD! 1988 GT - shorty headers, o/r h-pipe, flowmaster catback, pro 5.0, 4.10's
Posts: 144
Joined: 8/7/2007 From: Issaquah, WA Status: offline
my car does the same thing and when its cold it can be really cold blooded so i cleaned the iac and no better so i bought a new one and its a little better.....but not fixed so i guess its just one fo those SD car woes lol
< Message edited by rebel_yell -- 5/15/2008 10:31:28 PM >
_____________________________
88 LX 5.0- MSD cap,rotor,wires,and blaster coil, BBK shorty 1 5/8" headers, o/r h-pipe, K&N air filter, MAC 70MM TB P&P''''d, 3.73''''s, 14.532@95 mph (stock) hoping for 13s this summer!
When I first got my 88, it surged like that too. I did just about everything. Cleaned the IAC, pulled the throttle bottle and EGR spacer apart, cleaned them. Replaced the EGR, throttle body and IAC gaskets. Installed new plugs, wires, cap, coil and rotor. Also replaced the fuel filter. The surge is nearly gone now. I also cleaned lubbed and adjusted the throttle cable/bracket/spring. Another suggestion you could try is to get an adjustable fuel pressure regulator.
Printable Version
Idle Problems plus rpm hang - 
