1991 Corolla running rough?

neojoneswd · 30 Oct 2011, 03:10 am

car feels like its misfiring, rough on cold starts but after warm or running on freeway at higher rpms seems to smooth out with hardly any missing. i changed rotor and plugs when it started but did not help. any ideas on what might be wrong. had engine block replaced a year ago, tranny too. someone said maybe intake leak somewhere? changed wires a year ago. help? cannot afford a shop diagnosis AND repair same time.

Petie · 30 Oct 2011, 03:25 am

Well when you had your engine block replaced who did it? You and your partner or who (good mechanic?)? Did it run bad when they changed it or is it just starting this problem? Can you take it back to the guy who changed your block? I would assume the valves are not opening and closing correctly on your heads. Have the lifters adjusted (under the valve covers).

HOLEY MUFFLERS · 30 Oct 2011, 03:40 am

guessing? egr, cold start injector, IAC-idle air control valve, or associated or general vacuum leak. maybe pcv valve.

you don't have to take it in for diagnosis. you can do it yourself. easy!

this is an obd1 system. only special tool needed is a 6" piece of wire and two alligator clips to jump two terminals in the bay and the ignition blinks at you.

location of data link connector box,

http://www.autozone.com/autozone/rep...00c1528006f28e

how to pull the codes,

http://www.autozone.com/autozone/rep...00c1528006f294

what they mean,

http://www.autozone.com/autozone/rep...00c1528006f299

FYI,

not all codes stored prompt a light. so pull 'em regardless. codes pointing to sensors do not necessarily mean a sensor is bad. they should be tested first. then question the environment or components they monitor. best to start with a good base line so trouble shooting is not skewed. that means a fresh tune up. your distributor cap?????? very important. they get carbon tracks from arcing over time.

good luck!

1991 Corolla running rough?

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