{"model": "openai/gpt-oss-120b", "provider": "Groq API (free tier)", "task": "auto-diag", "prompt": "Write a step-by-step diagnostic walkthrough for high school automotive students: a 2012-2018 gasoline car comes in with a check engine light and code P0300 (random/multiple cylinder misfire). Show the logical order of tests from simplest to most involved, what tools are needed, what each result means, and safety notes. Format it as a student handout.", "system": "You are helping a high school career and technical education (CTE) teacher. Produce classroom-ready material.", "temperature": 0.3, "ran_at": "2026-10-16T05:19:52-0700", "output": "**High\u2011School Automotive \u2013 Diagnostic Handout**  \n**Vehicle:** 2012\u20112018 gasoline\u2011engine car  \n**Symptom:** Check\u2011Engine Light (CEL) on, DTC **P0300** \u2013 \u201cRandom/Multiple Cylinder Misfire\u201d  \n\n---\n\n## 1. Safety First  \n\n| # | Safety Action | Why It Matters |\n|---|---------------|----------------|\n| 1 | **Wear safety glasses & gloves** | Protect eyes from debris and chemicals. |\n| 2 | **Engage the parking brake** | Prevent the vehicle from moving while you work. |\n| 3 | **Turn off the ignition & remove the key** | Avoid accidental engine start. |\n| 4 | **Disconnect the negative battery terminal** (or use a **battery disconnect tool**) | Prevent electric shock and protect sensitive electronics while you probe circuits. |\n| 5 | **Ventilate the area** | Fuel vapors can accumulate in enclosed shops. |\n| 6 | **Never work on a hot engine** (wait \u226510\u202fmin after shutdown) | Burns from hot components and risk of fuel vapor ignition. |\n| 7 | **Use proper lifting equipment** if you need to get under the vehicle. | Prevent crush injuries. |\n\n> **NOTE:** Always follow your shop\u2019s standard operating procedures (SOPs) and wear the required personal protective equipment (PPE).\n\n---\n\n## 2. Tools & Supplies Needed  \n\n| Tool / Supply | Typical Model / Spec | Use |\n|---------------|----------------------|-----|\n| OBD\u2011II Scan Tool (or Bluetooth scanner + tablet) | e.g., Autel MaxiCOM, Launch X431, or a free app with a compatible adapter | Read/clear codes, view live data, perform cylinder\u2011balance test. |\n| Digital Multimeter (DMM) | 0\u2013600\u202fV, 0\u201310\u202fA, resistance mode | Test sensor voltage, coil resistance, continuity. |\n| Spark Plug Socket & Ratchet | 5/8\u201116 or 13\u202fmm (vehicle\u2011specific) | Remove/inspect/replace plugs. |\n| Torque Wrench | 10\u201330\u202fft\u2011lb range (per service manual) | Properly torque plugs, coil packs. |\n| Vacuum Gauge (optional) | 0\u201330\u202fin\u2011Hg | Check for intake leaks. |\n| Fuel Pressure Gauge (optional) | 0\u201380\u202fpsi, with appropriate adapter | Verify fuel system pressure. |\n| Compression Tester | 0\u2013300\u202fpsi | Test cylinder compression. |\n| Inspection Mirror & Flashlight | \u2014 | See hard\u2011to\u2011reach areas. |\n| Clean Rags, Brake Cleaner, Carb\u2011cleaner spray | \u2014 | Clean plugs, coil boots. |\n| Service Manual (or OEM repair guide) | 2012\u20112018 model year | Torque specs, wiring diagrams. |\n\n---\n\n## 3. Diagnostic Flow \u2013 From Simple to Complex  \n\n> **Goal:** Eliminate the most common, inexpensive causes first.  \n> **Tip:** After each test, **record the result** (e.g., \u201cPlug #3 \u2013 0\u202f\u03a9 (open)\u201d). If a test points to a definite fault, **repair/replace** before moving on.\n\n---\n\n### Step 1 \u2013 Verify the Code & Gather Live Data  \n\n| Action | How\u2011to | What to Look For |\n|--------|--------|------------------|\n| 1.1 Connect OBD\u2011II scanner and read codes. | Plug scanner into the OBD\u2011II port (under dash). Select \u201cRead Codes.\u201d | Confirm **P0300** is present. Note any additional codes (e.g., P0171, P0420) \u2013 they may be clues. |\n| 1.2 View live data. | Choose \u201cLive Data\u201d \u2192 select **Engine RPM**, **MAF**, **TPS**, **O\u2082 sensors**, **Fuel Trim**, **Misfire Count** (if available). | \u2022 RPM should be stable.<br>\u2022 Large positive/negative fuel trims (>\u00b110\u202f%) suggest fueling issues.<br>\u2022 Misfire count per cylinder may show a pattern even if P0300 is random. |\n| 1.3 Clear codes and test\u2011drive. | \u201cClear Codes\u201d \u2192 start engine, let it idle 1\u202fmin, then drive 5\u202fmin at 30\u201140\u202fmph. | If CEL returns immediately with P0300 again, the problem is still present. If it disappears, the issue may be intermittent (e.g., loose plug). |\n\n**Interpretation:** A clean scan with no other codes narrows the focus to the ignition/fuel system. Additional codes can direct you later (e.g., P0171 \u2192 possible vacuum leak).\n\n---\n\n### Step 2 \u2013 Visual & Auditory Inspection  \n\n| Action | How\u2011to | What to Look For |\n|--------|--------|------------------|\n| 2.1 Open the hood & inspect the engine bay. | Look for cracked hoses, loose clamps, oil leaks, damaged wiring. | \u2022 Cracked **vacuum hoses** \u2192 possible lean condition.<br>\u2022 Wet or oily **spark plug wires/coil boots** \u2192 misfire. |\n| 2.2 Listen for abnormal noises at idle. | With engine at ~800\u202frpm, listen for \u201cpopping\u201d or \u201csputtering.\u201d | Popping may indicate a **fuel delivery** issue; sputtering can be a misfire. |\n| 2.3 Check the **spark plug condition** (quick visual). | Remove one plug (any cylinder) with spark plug socket. | \u2022 Fouled (oil, carbon) \u2192 replace all.<br>\u2022 Wet with fuel \u2192 fuel system problem.<br>\u2022 Burnt tip \u2192 ignition problem. |\n\n**Result:** If you see obvious damage (e.g., broken coil boot), repair it now and retest. If everything looks normal, continue.\n\n---\n\n### Step 3 \u2013 Spark Plug & Ignition System Test  \n\n| Action | Procedure | Expected Result | Interpretation |\n|--------|-----------|-----------------|----------------|\n| 3.1 Remove **all** spark plugs. | Use socket, label each plug with cylinder number. | Clean, light gray\u2011brown insulator; no oil or fuel. | If any plug is fouled, replace **all** plugs. |\n| 3.2 Measure **plug gap**. | Use a feeler gauge; compare to spec (usually 0.030\u20130.040\u202fin). | Gap within spec. | Incorrect gap can cause misfire \u2013 adjust or replace. |\n| 3.3 Test **ignition coil resistance** (if coil\u2011on\u2011plug). | Disconnect coil connector, measure primary (\u22480.5\u20132\u202f\u03a9) and secondary (\u22486\u201312\u202fk\u03a9) per service manual. | Values within spec. | Out\u2011of\u2011range \u2192 replace coil. |\n| 3.4 Perform a **spark test** (optional, for schools with a spark tester). | Connect tester to plug boot, crank engine, watch for strong blue spark. | Strong, consistent spark on each cylinder. | Weak or no spark \u2192 ignition component fault. |\n| 3.5 Re\u2011install plugs (new or cleaned) and torque to spec. | Use torque wrench (\u224813\u201320\u202fft\u2011lb, check manual). | Proper torque. | Over\u2011tightening can damage threads; under\u2011tightening leads to poor heat transfer. |\n\n**Result:** If any plug, coil, or boot is defective, replace the part(s) and clear the code. Re\u2011scan; if P0300 persists, move on.\n\n---\n\n### Step 4 \u2013 Fuel System Check  \n\n| Action | How\u2011to | What to Look For |\n|--------|--------|------------------|\n| 4.1 Check **fuel pressure** (if vehicle has a serviceable fuel rail). | Connect fuel pressure gauge to test port (usually on the rail). Turn ignition ON (engine off) \u2013 pressure should match spec (e.g., 40\u201355\u202fpsi). | Low pressure \u2192 weak pump, clogged filter, or regulator. High pressure \u2192 regulator stuck. |\n| 4.2 Inspect **fuel injectors** visually. | Look for leaking fuel around injector tips, cracked injector seals. | Leaking injector can cause a rich condition \u2192 misfire. |\n| 4.3 Perform an **Injector Balance Test** (if scanner supports it). | Select \u201cInjector Test\u201d \u2192 command each injector to fire while engine runs. | All cylinders fire evenly \u2192 injectors likely OK. One cylinder weak \u2192 suspect that injector. |\n| 4.4 Listen for injector \u201cclick\u201d with a mechanic\u2019s stethoscope. | Place stethoscope on injector body, engine idling. | Consistent click each injector. No click \u2192 injector not pulsing. |\n\n**Result:** If fuel pressure is out of spec or an injector fails the balance test, replace the faulty component(s) and re\u2011scan.\n\n---\n\n### Step 5 \u2013 Air Intake & Vacuum System  \n\n| Action | Procedure | Expected Reading | Interpretation |\n|--------|-----------|------------------|----------------|\n| 5.1 Scan **MAF sensor** voltage/current (if equipped). | Live data \u2192 MAF voltage (0.5\u20134.5\u202fV). | Voltage proportional to airflow. | Erratic or low reading \u2192 dirty MAF. Clean with MAF\u2011safe spray. |\n| 5.2 Check **vacuum lines** for cracks/disconnections. | Visually inspect and **spray carb\u2011cleaner** into each line while engine idles. | Engine RPM should **increase** slightly when a leak is sprayed (extra air). | If RPM spikes \u2192 leak at that location. Replace hose. |\n| 5.3 Perform a **vacuum leak test** with a gauge (optional). | Connect gauge to a vacuum source (e.g., intake manifold). | Typical idle vacuum: 17\u201322\u202fin\u2011Hg. | Low reading \u2192 leak. |\n| 5.4 Inspect **PCV valve** and **air filter**. | Remove PCV, shake \u2013 should rattle. Replace if clogged. | Clean filter, unrestricted airflow. | Clogged PCV can cause rough idle/misfire. |\n\n**Result:** Fix any leaks, clean MAF, replace PCV if needed. Re\u2011scan; if P0300 remains, continue.\n\n---\n\n### Step 6 \u2013 Compression Test  \n\n| Action | How\u2011to | What to Expect |\n|--------|--------|----------------|\n| 6.1 Warm engine to normal operating temperature (\u2248200\u202f\u00b0F). | Drive the car for a few minutes, then park. | Warm engine gives accurate compression. |\n| 6.2 Disable ignition (remove coil packs or disconnect spark plug wires). | Prevent engine start while testing. | Safety. |\n| 6.3 Screw compression tester into each spark plug hole (one at a time). | Crank engine 4\u20136 revolutions, record pressure. | All cylinders should be within **10\u201115\u202f%** of each other (e.g., 150\u2013180\u202fpsi). |\n| 6.4 Compare results. | Note any cylinder low by >15\u202f% of the highest reading. | Low compression \u2192 mechanical issue (valve, piston ring, head gasket). |\n\n**Result:** If a cylinder shows low compression, the misfire is likely mechanical. Recommend a **mechanical inspection** (valve train, head gasket) \u2013 beyond the scope of a basic CTE lab, but note it for the instructor.\n\n---\n\n### Step 7 \u2013 Exhaust & Emissions Sensors  \n\n| Action | Procedure | What to Look For |\n|--------|-----------|------------------|\n| 7.1 Scan **O\u2082 sensor** data (pre\u2011 and post\u2011catalyst). | Live data \u2192 voltage (0\u20131\u202fV). | Rapid switching (0.1\u20130.9\u202fV) indicates healthy sensor. |\n| 7.2 Check **catalyst efficiency** (if scanner shows). | Look for \u201cCatalyst Efficiency Below Threshold.\u201d | A clogged catalyst can cause back\u2011pressure \u2192 misfire. |\n| 7.3 Inspect **exhaust manifold** for cracks or leaks. | Visual & listen for ticking at idle. | Exhaust leaks before O\u2082 sensor can cause false readings. |\n\n**Result:** Replace faulty O\u2082 sensor or repair exhaust leak if found. Re\u2011scan.\n\n---\n\n### Step 8 \u2013 Final Verification  \n\n1. **Clear all codes** with the scanner.  \n2. **Start the engine** and let it idle for 2\u20113\u202fminutes.  \n3. **Take the car for a short road test** (5\u201110\u202fmin, varying RPM).  \n4. **Re\u2011scan** \u2013 if **P0300 is gone**, the repair was successful.  \n5. If the code **returns**, document which tests have already been performed and discuss next\u2011level diagnostics (e.g., ECU software update, crankshaft position sensor, camshaft sensor, or internal engine damage).\n\n---\n\n## 4. Quick Reference Flowchart (Text Version)\n\n```\nStart \u2192 Scan OBD \u2192 Confirm P0300?\n   |\n   V\nVisual/Audio Inspection \u2192 Any obvious damage? \u2192 Yes \u2192 Repair \u2192 Re\u2011scan \u2192 Done\n   |\n   V\nSpark Plug & Ignition Test \u2192 Bad plug/coil? \u2192 Yes \u2192 Replace \u2192 Re\u2011scan \u2192 Done\n   |\n   V\nFuel System Check \u2192 Pressure/Injector fault? \u2192 Yes \u2192 Repair \u2192 Re\u2011scan \u2192 Done\n   |\n   V\nAir/Vacuum System \u2192 Leak or MAF dirty? \u2192 Yes \u2192 Fix/Clean", "finish_reason": "length", "usage": {"queue_time": 0.230341894, "prompt_tokens": 171, "prompt_time": 0.007300133, "completion_tokens": 3000, "completion_time": 6.29075435, "total_tokens": 3171, "total_time": 6.298054483, "completion_tokens_details": {"reasoning_tokens": 154}}}