hi,
this weekend i replaced both my upper and lower intake manifold gaskets on my 99 isuzu rodeo 3.2L V6.

It cranked fine and idled fine with no CEL lights. i let it sit for about 30 minutes and had to leave to go get something from autozone. as i backed out of the garage, the CEL turned on and was solid. i just ignored it since i was on my way to autozone anyway. when i popped it into drive at the end of the driveway, the CEL started flashing really fast. i pulled back into the garage to check out everything.

i checked all of the hoses and fuel injector wires that i had undone to change the gaskets. i did a google search and found out that flashing CELs mean misfires. i don't see how i could get a misfire if the injectors look good and i didn't touch the spark plugs.

forgot to say... the CEL only flashes when you mash the gas. if it's left to just idle, the CEL stays lit solid.

any ideas?

Sounds like a missfire to me.

How old are your sparkplugs?

Typically, if it's a missfire, the CEL won't flash at idle, but WILL when you're giving it gas.

rest the battery and see if it comes back.

The first time I cleaned the throttle body I had a flashing CEL when using the throttle. The next time I restarted it went away.

the spark plugs are about 3 years old. i figured that if they were bad, they would have been bad before i started working on the gaskets. it could just be that they just happened to go bad on the day i worked on the car.

i already tried leaving the battery unplugged for about an hour. last night before i went to bed, i unplugged the battery again. i haven't tried it yet today. one of my friends is coming over that knows a lot about cars.

i'm going to try finding the jumper wire (as suggested in a few other threads) so i can get the CEL to flash a number code. maybe that will tell me which cylinder is misfiring.

is there anything on the back of the upper intake manifold that might cause a misfire? i kind of had to wrestle with the upper piece so i could get it high enough to pull the gasket out.

How is it running?

i fixed it.

i went to autozone and used their loan-a-tool service to get a odbII scanner.

i got code P0204 Injector Circuit Malfunction - Cylinder 4.. i already suspected that it had something to do with the injector wiring.

i checked the wiring and in the process, accidentally pulled the little blue tab all the way out. i figured i'd go ahead and try it, since the wires seemed much easier to push in. voila... no more CEL or flashing CEL. the engine runs smoother now.

i got the blue piece back in and no longer have any codes in the system.

yay autozone and their loan-a-tool (FREE!) program.

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stephen