Engine misfiring, im so stumped...

[86MCSS]

When I start the engine it goes to the 1500RPM range at idle and surges and just misses like you wouldn't believe. Once at operating temperature it idles 900RPM to 1500RPM almost stalling and missing every time.
All readings on the Pocketlogger look normal. I cannot get a proper vacuum reading because the engine is missing. It stays about 10in of vacuum with this problem. Before it was at 20 , and 25HG at full clutch downshift. It also has no codes or CELs.

-I have done the following to attempt to resolve the issue-

-Installed new BPR8ES @28gap
-Performed injector disable and engine balance test. Every injector was at 2.3 Pulse Width@ 5% Duty Cycle and reacted normally.
-Tested ISC coils all between 28 and 30ohms
-Replaced BISS Screw O-ring
-Removed TB Elbow and TB and cleaned it very well
-Checked all wiring connections and inspected harness integrity.
-Replace Fuel Filter not to long ago
-Cleaned Air Filter
-Changed Oil
-fuel pressure is at 32psi at idle
-fuel pump voltage was 11.9 at idle and did not fluctuate
-logger shows karman on maf as normal
-Tested and even swapped in a known good working ISC motor
-Brand new ECU with replaced caps
-compression check resulted in 185psi[edit] straight across the board
-checked coil pack and the spark is very strong when plug wires are removed [checked at night]

Im lost and frustrated and mad damn it. I sold my perfectly good truck so I could have an economic yet powerful 4cyl and its nuttn but a pain. My damn 500 hp Monte SS doesnt give me this many problems!!!!

 

[andymoraitis]

Correct me if I'm wrong, but shouldn't fuel pressure be 37 PSI at the rail? That's the first thing that seemed out of whack. Also,why not run a BPR7ES (one heat range warmer) as the 8ES seems to be more for very high HP applications.

Keep us posted and good luck!

 

[86MCSS]

I tried playing the fuel pressure a bit but it still misses and idle surges a lot.

Im swapping in some BPE6ES plugs today because I have an extra set laying around.


How could I check my computer to see if its gone bad other than checking for bad capacitors and if it "smells funny". Does mitsu test them?

All advise is needed and welcome....

 

[oldman]

Do a pressure test and look for vacumm leaks, you could be sucking in unmetered air.

 

[andymoraitis]

Oldman's got a point. I was having some idle surge from my intake not being attached to the turbo properly. I was sucking in unmetered air and the car hardly wanted to run.

 

[86MCSS]

Long story short, I took it to my uncle who is a mechanic he looked it over and was stumped for about a 5 mins then checked my boost guage seen I had 10 inches of vacuum and said my timming was off. I checked it and it was off 5 teeth . That solved the misfiring and the surging was the ISC motor. It all went bad and happened in the same day. I still dont know how it jumped so many teeth because the belt was still nice and tight, I didnt chance it though and replaced the tensioner. Its fixed now.

Boy do I feel stupid.

Thanks to everyone who helped I appreciate it.