Engine Car miss firing at 3200 rpm

08GT500 said:

Hi,
Sounds like an interesting ride. Like any motor, it requires the essentials.. Any questions, please ask. Can you pls.snap a Pic or two of the Motor to aid in diagnostics?
The Car’s running EFI, correct? It needs the O2 Sensors to initiate EEC’s closed loop, partake in A/F Ratio calculations.. You have an AEM Wideband Air/Fuel Gauge, correct? Aftermarket ignition components are significantly more prone than OE to fail, or cause issues such as this*.
Does the problem seem to be only RPM related, and occurs regardless of how much or little the throttle is open, & does the car “jerk” when this occurs, how does this ‘miss’ present?
Buy OEM replacement ignition parts/Sensors when required. I’d start with these, some are questions, other’s- Tests...
1) Is there a Check Engine light ? Locate any Codes, ether way, what did you find?. Pull with an OBD-1 reader, or by Jumping the DTC, reference: http://sbftech.com/index.php/topic,2471.0.html
2) Buy a Can of CRC MAF cleaner & spray the MAF Sensor clean & verify everything to the T.Body is clean/ clamps tight with no CAI leaks.
3) Have you altered Timing with the SPOUT jumper removed, then reinstalled? Run Timing conservatively at 10-12 Degrees until you locate the issue(s)..
4) What is your fuel pressure at the rail? Should be >/= 30-35lbs.
5) Pull the TFI, Autozone tests them for free. Bring a hairdryer and hit the TFI with heat during the testing to simulate engine heat.
6) What Color were the Plugs electrodes, what “deposits” are you referring to that made you jump up one heat range?
7) Sounds like the EEC goes to closed loop when the issue starts. 02’s need be the correct temp for closed loop to occur. Verify both 02’s are connected, may have a melted wire on a header.
8) Check your Engine Coolant Temp Sensor. Ones for the Gauge, Pass. side is for CPU. Pull the plug & measure Resistance with a VOM when Coolant is cold, also when hot.
Verify your Coolant level is topped off.
9) Pull & clean, apply anti-corrosive & reinstall your Grounds so they’re solid. Battery to Block, Block to Chassis, Battery to EEC, Battery to Chassis. Test Battery to Dizzy’s Chassis with a VOM.
10) Pull and inspect the #3924 Plugs. What color are the electrode(s)? If they appear Carbon fouled, I’d suggest you pull back the gap to 0.035.
11) Pop the Dizzy Cap off, pull the Rotor, remove the 2 screws below & clean any corrosion off any surfaces with light paper, blast the inside out with CRC MAF cleaner.
Hall Effect Sensor..
12) Is there any possibility there’s a 2 Step, or a launch control present that you may have enabled, that may be getting triggered?
FYI:
Top causes for this issue: Dirty MAF, Bad Plug Wire, TFI, fouled Plug(s) Dizzy or weak Spark.


The above should yield you some results, any questions you answer will help.
Good luck!
-John

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