CEL is flashing, HELP!

[sopaul808]

Hello everybody, I own a 98 Rodeo 6cly. 4x4 automatic. Recently i been experiencing some weird idle and hard start, sometimes stalling. So i had the code read and they said my cylinder 3 is misfiring. So i went ahead and change the spark plugs since i haven't done so since i bought the vehicle. But it didn't help, still experiencing the same thing so i read on it some more and some said it might be the EGR needs cleaning. I went and got some carb cleaner and begin cleaning while i was cleaning I smell this weird odor coming out from the exhaust, is this normal? After cleaning it and clearing out the codes the vehicle runs fine for a good 10 minutes and the CEL pop back up and is flashing. When i accelerate, as the vehicle shift from 1st to 2nd it'll jerk almost like a thump and when it shifts back down from 2nd to 1st it'll jerk. It shake very hard and would stall most of the time when i come to a complete stop, but when i cleared the code it drives fine until the CEL pops out again and start flashing. I got the code read and here they are.....
p0121, p0300, p0171, p0174
Did i break anything while cleaning the EGR? any suggestion would greatly appreciate it. Thanks in advance.

[marcre]

It may very well be the IMG(intake manifold gasket). I'm pretty sure the 98's had issues with those as well. When I had my 99 it acted the same way when it went bad.

[amigo-2k]

5 of the coils are the same and 1 is different The one by the brake master cyl is different.

the #1 cause for a mis-fire code is a leaking intake manifold gasket (I had mine replaced 2x within the first 75k miles).

Cost at a dealer to replace is 350-400 bucks.

The parts cost under 40 bucks.

click on my FAQ link below for more details on how to test for a leaking intake manifold gasket.

[sopaul808]

Thanks, im going to order the parts and replace it this weekend.

[sopaul808]

Guys i didn't change my IMG but i check my spark plug for oil and wetness and i found my 3rd and 5th cylinder were a little wet. so I put it back together and when i start my vehicle i see smoke coming out from the engine under the spark plug area and my CEL starts flashing. Could it be because i spray to much carb cleaner around the manifold area or does it mean my engine is shot. This is my first atemt at changing spark plugs. and i hear ticking sounds from my engine after i shut it off. Is this knocking sounds? Please help!

[sopaul808]

Just figure out why the engine was smoking. When i spray the brake cleaner around the manifold it didn't completely evaporate so when i start the car it just started smoking off the rest of the brake cleaner, lol.