help with diagnosing a couple problems...

[shaunmy]

first off, the car is a 91 turbo FWD with 95k on the clock, and is 100% stock.

i am having an issue with shifting. sometimes its extremely hard to go into gear, sometimes it goes into gear with no problems. i have recently replaced the clutch slave and master cylinders, (there is no air in the system, so forget that option) and the clutch pedal is adjusted well. it seems like it does it more when its cold but maybe thats just me. it also does it when the car is completely warmed up sometimes. usually when it happens, it comes and goes in spurts. for instance it will be hard to shift almost the entire way to work one morning and that night it will shift awesome. the transmission fluid was replaced about 5k miles ago with pennzoil syncromesh. the clutch pedal is just as stiff every time i push it.

all i can think of is sticking synchros, or maybe something is worn in the clutch pedal assembly? like i said it is not air in the system. the shifter cable bushings look fine as well, and i would think like if the shift fork was bent it would be more of a continuous problem....
EDIT: car shifts perfectly fine with engine turned off.


the other issue i am having has to do with the car accelerating and idling. when i turn my headlights on, my motor will slow down by about 200rpm. and when i am sitting at stoplights my dash lights will become a little bit dim unless i give the car some gas. it also randomly idles either very smooth, to a little rough, to sometimes noticeably rough.

part two of that issue (i think it may be related) sometimes when i am accelerating, the car will come in and out of accelerating. it almost feels like fuel cut, but it comes in spurts. for instance, while in second gear, accelerating at about half throttle, it may cut out 3 or 4 times before i shift to 3rd gear. and if i floor it when its doing that, my car feels as slow as a honda () it almost is like im getting huge amounts of knock and the ecu is retarding timing a lot (i run 92-93 octane always) this does not happen very often though, maybe once every couple of days. and spark plugs/wires are good and new, respectively.

there are a million things i could guess for this, thats why i am asking if anybody has any experience/ideas with these issues. IAC? TPS? ECU? maf maybe? i have no idea where to begin looking.

thanks for any input,
shaun

 

[freshlane]

for the lighting issue make sure your car has all the ground wires connected and make sure your alt is charging as it should. Do you have any CELS? Does it act weird at idle?

 

[steve]

the other issue i am having has to do with the car accelerating and idling. when i turn my headlights on, my motor will slow down by about 200rpm. and when i am sitting at stoplights my dash lights will become a little bit dim unless i give the car some gas. it also randomly idles either very smooth, to a little rough, to sometimes noticeably rough.

part two of that issue (i think it may be related) sometimes when i am accelerating, the car will come in and out of accelerating. it almost feels like fuel cut, but it comes in spurts. for instance, while in second gear, accelerating at about half throttle, it may cut out 3 or 4 times before i shift to 3rd gear. and if i floor it when its doing that, my car feels as slow as a honda () it almost is like im getting huge amounts of knock and the ecu is retarding timing a lot (i run 92-93 octane always) this does not happen very often though, maybe once every couple of days. and spark plugs/wires are good and new, respectively.

Sounds a lot like one of the symptoms of leaking capacitors in the ECU.

The difficulty maintaining idle speed would be from a bad Idle Speed Control (ISC) motor or damage to the ISC drivers inside the ECU.

Is the check engine light on when the car hesitates?

Steve

 

[MyÜberFastGSX]

The shifting problem could be due to bent shift forks, or your clutch not fully engaging. Or a combination of the two.