'91 N/A MR2 running like crap

[cakemashin']

ok, my car has an automatic tranny. whenever the car is cold, it hesitates while accelerating. you can leave the gas pedal in the same spot and it will resist accelerating for a few seconds and finally it will take off. it doesn't do it really when it is warm, but i do feel a lack of power it seems. it has been doing this for the past 5 or 6 months and i'm tired of trying to figure it out. i have changed plug wires, cap & rotor, egr valve, egr vacuum module, and the throttle position sensor, and cleaned the throttle body. the plugs and fuel filter were changed about 15k miles ago. i have spent over $500 dollars in parts to try to fix this problem and i have gotten nowhere. part of me kinda thinks it is the tranny. i changed the fluid about 15k miles ago but didn't clean the filter... i'm kinda thinking that whenever it is cold that the fluid may be gunked up?...maybe? i don't know. any help is appreciated. ALSO can anyone tell me how to change the inner and outer tie rods?

[MR2-MRnot]

timing? i know my timing was retarded (turned way down) and it ran like a cow, i then advanced it as far as it would go (without ticking and knocking) and voila runs like a raped ape! i recomend u try this and see wat happens! hope this helps!

[cakemashin']

oh yeah well i had the timing and the valves adjusted also a few months ago to try to fix the problem(forgot to mention that). i didn't do it cuz i don't exactly know how and don't have any resources close by. BUT whether the shop actually adjusted it all or not... only God knows. thanks i will try to get my dad to help me adjust it and see if that works

[honda_bar]

Hmm, well I have the SAME EXACT problem with my other car, so I feel your pain. I'm guessing that is has something to do with the trans though. Any advice would be nice!

[fvillota]

well i have an automatic tranny and i have days that it runs awesome and i have days where it runs like pure crap! umm.. but try ur timing and did u adjust ur tps right?>

[cakemashin']

i changed the tps....but the TPS is adjustable?????

[fvillota]

yes sir!! i im certain. makes ur car run lean and or richer

[cakemashin']

how do you adjust it?

[fvillota]

well you need to have to search it on here because im not 100 percent sure i just know u lossen up the 2 screws and twist it up and down. u might see rpms go up n down. but to tell u the truth i dont really know because i adjusted mine half ass

[cakemashin']

k, i will give that a try too. but those screws are a pain in the ass to get to. gonna have have to pack a heavy good mood when i try to adjust it thanks for the input

[Gairloch]

I am seriously disinclined to look at the transmission for this problem. It's much more likely to be an electrical issue of some sort.

If you have a multimeter you might want to go through the BGB to find the diagnostic procedure and go nuts on it. Personally I'd start with the o2 sensor.

[fvillota]

yea i agree. try that tps adjust (and yes the screws suck) try changing the o2 sensor and also make sure ur timing is not retarded. remember to not just move the distributer u have to jump the terminals on the diagnostic box 1st or the ecu will just re time it.

[Gairloch]

No, don't change the O2 sensor, test it first. Throwing parts at a problem is a really good way to emtpy your wallet without actually resolving anything.

[fvillota]

yea i guess thats true.. not really thinking money wise. but yea ur best bet is to test all these components and see if it helps

[cakemashin']

ONE OTHER THING I FORGOT TO MENTION: the car starts fine and idles fine. there is NO hesitition when you rev it up from an idle. the hesitation/ resistance only happens when driving

[cakemashin']

Well i am once again on this thread because after almost 10 months, i am still having this same issue. when the car is cold it resists during acceleration. it seems to struggle moreso in 3rd gear as you very first take off. then if you slow down or stop and go back to 1st gear and speed back up, it has trouble with 1st, 2nd, and 3rd gears.

i took it to a pretty good mechanic a few weeks ago. he changed the ECT sensor (he was suspecting that it was the cause of the problem), but it turns out that the ECT sensor fixed ANOTHER problem... (when cold, the car was having trouble shifting into overdrive when it was supposed to... he thought the two problems were linked). the new ECT sensor fixed the shifting problem, BUT IT IS STILL RESISTING AND there is no "check engine" light.

THINGS I HAVE DONE/ REPLACED:

changed plugs, plug wires w/ stock wires, cap and rotor

changed egr, egr vacuum module

changed tps

had valves adjusted

had timing checked and adjusted

unplugged the o2 sensor... (no change in performance)

changed fuel filter about a year ago (going to change it again soon)

ECT sensor was changed by mechanic

THINGS THAT I AM ASSUMING COULD BE WRONG:

fuel pump?

bad fuel pressure?

fuel filter?

transmission has leak...maybe causing some of the problem???

tps needs adjusting?

timing checked again?

bad vacuum hose somewhere?

bad catalytic converter?


these are just some guesses. i am weary of who i take my car to because i don't trust a lot of people to work on it, and i don't want to get charged several hundred dollars for a shop to tell me that they can't find the problem. then again it is pointless to keep spending money on parts that won't fix it.

anyways, this is really frustrating to deal with this every day. ANY input would be greatly appreciated.

btw, where can you get toyota scanners for our cars?... supposedly '91s are pre-OBD 1

[MR2 Drifter]

If anything, my cousin had the same problem in his mazda, it ended up being his ECU

and if it only happens when the cars cold then let it warm up before you drive it

[fvillota]

adjust the tps.. lol ive been running mine unplugged and car drives like a dream... cept for the rich part and its like im driving a v8

[cakemashin']

Originally Posted by MR2 Drifter

If anything, my cousin had the same problem in his mazda, it ended up being his ECU

and if it only happens when the cars cold then let it warm up before you drive it

I thought it may be the ECU also. but even if you let it warm up after it has already been sitting at ambient temperature, it will still resist. and it feels lacking in power overall

[cakemashin']

Originally Posted by fvillota

adjust the tps.. lol ive been running mine unplugged and car drives like a dream... cept for the rich part and its like im driving a v8

i am going to unplug it right now. the reason i haven't adjusted is cuz my rpm gauge doesn't work lol... another problem haha. i will drive it to work and see how it runs. will update after i get home