Engine hiccups.. Help!

[wahed3001]

94 Camry 4cyl auto trans 130k miles.

When the engine is at idle and warmed up, every few seconds (but not at regular interval) the engine shakes, the rpm needle takes a dip, and the dashboard lights dim for a moment. It is more prominent when the car is in gear but stopped. I don't feel any hesitation while the car is moving. Also it takes a little longer to start the car as if the battery is weak (which it is not); It used to start instantaneously before. I've replaced the spark plugs, plug wires, distributor cap, and the rotor a week ago when the car suddenly started stalling and misfiring. This hiccup started right after the replacements. I tried looking for any vacuum leaks but couldn't find any. Now I'm completely clueless!

[dc_98_cam]

Have you cleaned the cable terminals on the battery lately?
Use a small fine wire brush...inside of cable terminals should be bright and shiny... the battery terminals themselves should also be bright and shiny.
Is the connector on the alternator snug...might be worth removing and cleaning with electrical contact cleaner... also the alternator ground terminal.
...Remember to disconnect the negative battery terminal whenever you work on the alternator or anything else involving the electrical wiring...an inadvertent spark might damage the ECU or some electrical sensor.... Replace when you are through and snug up all nuts and bolts.

[blackhawk]

^ yah i second that

[eurohazard]

I'd clean all the grounds in the engine compartment...not just at the battery (but it is a great place to start). I did this to mine a few years ago, and it helped tremendously. My headlights used to dim pretty good when my bass hit, and after I cleaned the grounds it was like night and day difference.

[wahed3001]

So you think a poor contact in the alternator or the battery terminals is causing the random jerks in the engine? It almost seems like that the engine suddenly dies for a moment and jumps right back up! A friend of mine told me that it might be the airflow sensor or the fuel line/filter acting up but I don't know where they are or how to check them. Anyway, I'll try cleaning the contacts tomorrow and get back to you. Thanks for your help!

[megamac83]

either the batter or I would look into a small lead in one of the many vacuume line!!!

[dc_98_cam]

A frequently reported problem with these cars is the ignition coil in the distributor.
As I understand it, there is some difficulty in positively diagnosing this part... something to do with temperature, vibration...There are some specs in the repair manual... but others have suggested just replacing it... or else get a replacement distributor from the salvage yard...Maybe just check the simple things first...battery, alternator, grounds...

[RichieRichJP]

Check the Ignition.