88 Camry-misfiring

[roscodog]

All of a sudden my engine started missing. It runs smooth for a few seconds, misses for a few seconds, smooths out again... intermittant but constant. New plugs, cap and wires didn't help. Timing is good. Valve lash is good. Fuel pressure in rail is good. Compression is OK, 170-165-150-170, a little low in number 3. Cleaned and checked wires to injectors. Listened to injectors with stethoscope while running, all sound good. Removed valve cover to check for weak or broken valve springs, seems fine. One thing, when it is missing there seems to be pulses out of the exhaust, no smoke, it just seems like one cylinder is pumping more air out for a second.

Any ideas? Thanks, Ross

Oh yeah, vacuum is good and steady too

[KimMG]

What did the #3 spark plug look like?

[roscodog]

Originally Posted by KimMG

What did the #3 spark plug look like?

Just like the other three, nice tan colour like they were burning fine.

Ross

[Mike Gerber]

Check the coil. These 3SFE engines had a problem with the coil developing a hairline crack inside the distributor and shorting itself to ground on any metal inside the distributor. The resulting problem can be intermittant as you describe. In addition, also change the rotor. You mentioned the cap and wires, but not the rotor. I have seen a few develop cracks underneath where the rotor sits on the shaft of the distributor. It's only a few dollars to replace the rotor.

Mike

[roscodog]

When I bought the cap they didn't have a rotor in stock, so they ordered one for me. It came in, I changed it and now the car runs like a top. Good call Mike.

Thanks, Ross

[Mike Gerber]

Originally Posted by roscodog

When I bought the cap they didn't have a rotor in stock, so they ordered one for me. It came in, I changed it and now the car runs like a top. Good call Mike.

Thanks, Ross

Glad it's running good for you again.

Mike

[idmetro]

My .02 worth is to go ahead and buy a replacement coil, put it in the trunk along with the necessary hand tools and a flashlight. Having had my coil fail 3 times over the life of my car (1991 with 200k miles) I would have been very grateful for the spare as it would have cost me some time but would have saved me a great deal of inconvenience. Besides it's like insurance: if you have it you won't need it.....