rough idle

[blackaneseazn]

hey everyone,
i've read previous forums relating to hard or erratic idling. my 90 celica gts is similar in that it starts rough on the idle but smooths out when the engine warms up. I also find that the throttle sticks a bit as when I push the throttle back in place the idle lowers even more.
i've already done a tuneup that includes: oil change, new distributor & rotor, new ignition wires, new iridium plugs, coolant change and thottle body cleaning. although previous threads have said that the problem is in the idle control valve, I have no idea what it looks like as the location area is all i know. i'll probably dump some fuel injection cleaner next to clean the injectors. other than that, i was hoping someone could offer me some solutions and describe it so i can better locate the problem. pictures or diagrams would be really helpful.

[89CelicaGTTurbo]

i had a similar problem. i had to replace the sensor located directlly under the throttle. the best was to spot the sensor is to trace the two coolent lines going under the throttle. that sensor detects the temp of the coolent and may be the cause of the rough idle.

[silverstreakin]

not to hijack this thread or anything

it does detect the temp of the coolant?? i unhooked mine when i did my tranny swap, and havnt had any problems....less the temp guage not working. i always thought of it as a power loss, and another chance for coolant to leak out.

[Pineapple]

Try some throttle body cleaner in the throttle body. Usually there are too much build up to prevent air flow at idle. Check cold injector and timing switch also.

[GT4Thug]

89CelicaGTTurbo didnt yours give an error code ?

mine did as i left mine off when the engine was put back in when i left it off and it had aged that much it broke when i did !!!!

quick checks....

1) READ ECU ERRORS.... this will give any ECU faults straight away! (note them down then remove the fuse and re- read) just incase it was a one off

2) if above gives any errors fix them or re-post

3) does it stall into junctions ? (check under the powersteering pump just in case the low idle has fractured)

4) any air/vacuum pipes come off ? (silly but errective drain)

5) do you have a BOV ? if yo is it chattering ? (piston opening and losing air metered by the AFM)

6) Think this is enough to get you going so post after doing the above hopefully if will point to something wrong and go from there !!

Stu!

[89CelicaGTTurbo]

no error codes

[GT4Thug]

should of given an error 22 ....

the joys of technology !!!