Ok well some of you guys may know i been bitching about my gas mileage for a while now... it got better but is going downhill again... 250 and light comes on...
ive gotten my Fuelfilter changed,Plugs + wires,ERG cleaned,o2 changed,oil change,tires are right, Throttle body cleaned, airfilter changed,

only thing i didnt do was Ignition timing, compression, and cat converter check...

well i got the ignition timing done at a local shop yesterday, things was ok after he did the job, after i got back home and later that night i started the car up, the idle will go around 2500rpm like most cars do, then itll drop a little to 2k rpm then 1500rpm, but then itll jump back up to 2000, then 2300, and slowly drop to 1500 range again and it will do that for a while till the car warms up then it goes back to normal... what can be the cause of the jumps?

and i usually drive on highways, now after i get off the highway theres usually a red light right there, when im at a full stop it idles at 1 for like 40 seconds then goes back to 700rpm..

is all this normal?? what can i do to fix it? or am i just paranoid....
thanks for all the help, sorry for the long read..

 

What happens when you give it gas? DOes the idle stay high and slowly comes back down?

Could be a sticking throttle cable or something..

fs

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by filthy_shovel &raquo;</TD></TR><TR><TD CLASS="quote">What happens when you give it gas? DOes the idle stay high and slowly comes back down?

Could be a sticking throttle cable or something..

fs</TD></TR></TABLE>

Do you mean while im idleing at a light or at start up? but some times u feel a slight choke but it doesnt hold long...

 

Reread your post. Try to look at the following:

First eliminate if the IAC control is at fault or not. Start the engine and allow it to warm up. By jumping a 10K (10,000) ohm resistor between ALDL terminals "A" and "B", the ecm will fix the IAC position, ignoring the internal timer, and be forced to go into closed loop, and set the idle speed to around 1000 rpm. If the idle speed still continues to fluctuate, you'll have other items to check out.

(1) Check for throttle cable binding or sticking

(2) Broken or loose motor mounts

(3) Problems with charging systems Multimeter across both battery terminals (must read over 14 Volts constant)

(4) Defective electrical components, such as a defective or misadjusted park/neutral switch, bad tps sensor (Check with a voltmeter from 1-5 volts), bad ground connections.

(5) Vacuum leaks, bad PCV valve- this can be checked by pulling the PCV from the valve cover, leaving it connected the vacuum hose to the intake. Place your thumb over the end of the valve, if the idle speed quits surging, replace the valve., defective vapor control system, leaky egr valve through base gasket

(6) Fuel pressure fluctuation

(7) A/C compressor clutch malfunction- (the A/C must be on for this to happen)

(8) uneven compression between cylinders (not very likely, but depends on the mileage of your car)

(9) MAP sensor. probably not the culprit, but it could be going out, or be leaking vacuum at it's base.

(10) Air pocket in the cooling system. Not very likely, but has happened before

Further, to test for a vacuum leak, spray wd-40 on suspected air leaks, if idle moves, then it is leaking.

good luck

fs