I am trying to figure out my random and catalytic damage misfires are coming from.

It is super bad at cold, until it gets up to operating temp (180*). Then depending on weather outside(warmer the better), It either goes away completely, or still is there.

I replaced the o2 sensors. Brand New Flow Matched/Tested Injectors. 1 year old MSD 8.8MM Wires, 6 month old NGK TR6 plugs.

If the computer pickup for water temperature is incorrect, could it throw it off, and pull timing/add fuel/etc to cause this issue?

I have milled heads w/ a cam. 11.7:1 compression Ratio.
2 years no problems like this prior.

Recently Tuned in an attempt to fix problem. I have perfect A/F Ratio ~13.X.

 

my coolant sensor went bad and when datalogging it would show -39 degrees and run so rich the car would flood out.....

 

I see. And this is the one that is on the driverside cylinder head behind the power steering pump?

Mine still registers in the dash, did yours when it went bad?

 

ECT sensor, or its connector, will whack the
operation big time if it's dead or simply flakey.
It could get better with just a pull & reseat of
the connector. Maybe inspect both for crust,
loose or pushed-back pins, etc.

 

A friend just had this happen on a 98 z28, the dash read fine, but the datalog was -3x degrees, causing all kinds of problems.

Try a datalogger to see what the pcm thinks the ECT is.

Ryan

 

no mine stopped....the 98 uses a 3 pole sensor....one wire comes from pcm,one wire is a return signal to the pcm,and the last wire operates the gauge.....do you have an ses light on.....

 

Yes, For Random Misfires.

And thanks for the input Jimmy and Slow.


If I wanted to check the 3-wire connector w/ a DMM, what would I need to do?

 

Bump. Replaced the ECT. No avail. Pulling and checking plugs on Sunday.

What about the IAT?

 

IAT is 12 bucks at autozone.

I replaced mine because I felt the k and n oil messed it up. I got a much better idle quality with the new one.

 

Its annoying just throwing parts at the car. So plugs and IAT are next. Thanks for tips. Any other suggestions?

 

Changed plugs/IAT.

The code changed to P0353 and P0327(KS B.1 Low Input) Both KS are brand new and harness is also. Had the same issue ever since I replaced them the first time(no codes, but tuner said they didnt appear to be workin well, so I replaced them). Installed properly, and checked continuity in wire).
P0353 is Primary/Secondary IGN Coil Malfunction (C = #3). So is Cylinder #3's coil bad or wiring harness or something?