Desperate for help...'97 V6 bad misfire cylinder 5
 

Tearing my mom's intake off for the 4th time attempting to fix or atleast diagnose a misfire in cylinder 5.
Have a new cap, plugs, injector, wires, timing belt(2 yrs old) and battery.
Planning on doing a compression test in the morning. Any ideas on the problem? Are these engines known for a certain fault causing this misfire? i've noticed i'm not the only one around with a cylinder 5 misfire.

and a second question. what is the compression I 'should' have on this car?
...it does have 160k on it.

Thanks for any help!

did compression test. (first time i've done one...)

first round of check
cylinder 1 - 175
cylinder 2 - 175
cylinder 3 - 200
cylinder 4 - 165
cylinder 5 - 200
cylinder 6 - 225

second round of testing they all showed 225 psi.

don't fully understand that, i let the engine warm up before i started testing.
also pulled sparkplug on cylinder 5 plugged it into the wire and cranked. saw a small spark with crackling on each revolution. (i hooked the threaded area up to a jumper cable and attached other side of cable to neg of battery). DId not see a spark religiously every revolution though, I DID hear crackling each revolution. I've understood that to be normal?
Either way it has a new plug wires and cap so spark should be fine.

anyways, where should i go next? still don't understand this cylinder 5 misfire.

do u have the gap right and what about champion plugs?

I did not regap the plugs. The plugs that were in it when this issue started were only two years old. I replaced the plug for that cylinder with a new one but still the same problem.

Two thoughts I had was maybe a bad computer or possibly a bad wire going to the cylinder five injector?

Car drives fine off idle, but at idle its terrible.
Cleared codes after compression test, still kicking cylinder 5 misfire code.

Like the web site!

more like internal engine like sticking valve or carbon on the valve the pcm does not make a single cly misfire on a distributor system.

hmmm that makes sense...
That wouldn't show up in a compression test?
guess there is no easy way of fixing that is there??

decarb the pistons

yeah i understand that... but is there anyway i can do that without having to pull the heads?

I've read posts about people putting seafoam into the intake to clean the intake valves?

that's what I as talking about directly into the intake and into the cyls it will make a lot of smoke.

so i'm putting this stuff in it while the car is running?
Or am i doing it with the car and intake off?
Thanks for your help