djsquare

So I bought my car with a slight misfire. You can't really notice it at idle, but you can tell as it shakes the car a bit in the 2.5K RPM range.

It's a 1998 Camaro Z28 with the LS1. It has headers, no cats with resistors in place, bored TB, and I don't know if theres an aftermarket cam or tune which could also be the problem.

My misfire history is showing the following:

1:250
2:8696
3:3101
4:0
5:7391
6:0
7:0
8:1979

I took it into a performance shop and they told me they ruled out spark, so that's not the problem. They said they doubt it machanical as well, so I will hold off on a compression test.

Apparently cylinder #2 is misfiring the worst when they hooked it up to their scanner, and that may be the cause as it's making the rest of the cylinders look like a misfire from the crank sensor..?

Anyways they told me to swap injectors #2 and #4 instead of them doing it so I could save some money, which I will get to later this week.

I don't feel like it could be an injector although anything is possible.
I am just looking for some feedback on what else could possibly causing this misfire. Also, what are the steps for removing the rail and injectors?

Thanks in advance,

Dustin

2000ultraZ1911

It's hard to say with a good scanner they should he able to look at all the sensors while its running...my buddy has a 98 and tryd a ported tb and it drove his nuts.

djsquare

My TB isn't ported but it has been bored and polished, although that couldn't be the case.

In the past I have picked up a P0300 Multiple/random misfire, P1404 EGR stuck closed and a P0440 EVAP issue, but those all went away and never came back (yet).

I cleaned the EGR and it hasnt set a code since. The EVAP was pretty random and only seen it once while driving.

I have my own scanner, and all the sensors look fine. The LTFT and STFT are within -+10, 02's look great, everything looks normal..Could a bad crank sensor cause this issue? Although a few cylinders have no MF history, so maybe not.. This is a tricky one..

Will update more after swapping injectors.

gagliano7

Swap coils to see if problem follows coil. I had a bad coil with no misfire codes. Car would idle a little rough and at part throttle. The way i found the bad coil i started car and with an infared heat gun checked the temp on each header primary and found #8 primary temp was alot lower than all the other primaries. Changed coil and problem fixed.