# Ignition System Inspection in Upland > Misfires or rough idle? Our Upland ignition system inspection reads misfire counts, tests coils and pulls plugs, with photos of worn parts in your report. Source: https://route66autorepairshop.com/diagnostics-and-inspections/ignition-system-inspection Updated: 2026-09-17 Business: Route 66 Auto Repair, 1775 W Foothill Blvd, Upland, CA 91786, (909) 608-7699 Hours: Monday to Friday 8 AM–5 PM, Saturday 8 AM–2 PM, Sunday closed **TLDR:** We read **misfire counts by cylinder**, test coils and wires, and photograph the **spark plugs** when they tell the story. An ignition system inspection at Route 66 Auto Repair in Upland checks the parts that light the fuel in each cylinder: plugs, coils, wires and their control. Weak spark shows up as a rough idle, a stumble when merging or a flashing check engine light. We read misfire data, test the coils and pull plugs when needed, and back the written findings with photos of the plugs themselves. ## Signs of an ignition problem - A flashing check engine light - Rough idle or a shake at stoplights - Stumbling or hesitation when accelerating up the 57 - Hard starting, especially in damp weather - Spark plugs that have not been changed in a long time ## How do we inspect the ignition system? Most engines count misfires for each cylinder. We read those counters on a road test to see which cylinder is missing and under what conditions. To find out whether the problem follows the ignition, we may swap a coil to another cylinder and see if the misfire moves. A misfire that follows the coil points to the coil. Coils and wires can be tested for resistance, and on many vehicles we look at the firing pattern with a scope. Spark plugs tell their own story: worn electrodes, oil fouling, carbon or cracked insulators. When we pull plugs, we photograph them in cylinder order, because the pattern across cylinders helps show whether the problem is ignition, fuel or mechanical. Coil boots are checked for cracks and tracking marks. ## What goes on the ignition report? - Misfire counts by cylinder and when they occurred - Coil swap or scope test results - Coil, boot and wire condition - Spark plug condition, with photos in cylinder order - Codes and whether a fuel or mechanical test is needed next ## Our ignition system inspection process 1. **Scan and road test:** We read codes and misfire counters under load. 2. **Isolate:** Coil swaps or scope tests show whether the ignition is at fault. 3. **Inspect plugs:** Plugs are pulled when needed and photographed in order. 4. **Report:** You get findings, photos and an estimate. ## What's included in an ignition system inspection - Code scan and misfire counter review - Road test under load - Coil and wire testing - Coil boot inspection - Spark plug inspection with photos when removed - Written findings ## Need-now or need-later? **Need now:** - A flashing check engine light, which can overheat the catalytic converter - A dead cylinder - Oil-soaked coil boots from a leaking seal **Need later:** - Plugs near the end of their interval with no misfire - A lightly cracked boot with no tracking ## How pricing and timing work The counter states the inspection fee before we begin. Plug access varies: some engines need the intake removed to reach the rear plugs, and the written estimate shows that. Misfires that turn out to be fuel or mechanical may need more testing, which we quote first. AAA members save 10% on parts and labor, up to $75. ## Read next Worn plugs lead to [spark plug replacement](https://route66autorepairshop.com/engine-services/spark-plug-replacement). A failed coil points to [ignition coil replacement](https://route66autorepairshop.com/electrical-services/ignition-coil-replacement). For a deeper electrical trace, see [ignition system diagnostics](https://route66autorepairshop.com/electrical-services/ignition-system-diagnostics). If the misfire is not ignition at all, [check engine light diagnostics](https://route66autorepairshop.com/engine-services/check-engine-light-diagnostics) takes the next step. ## Frequently asked questions ### Can you diagnose why my check engine light is on? Yes. We read the codes, then test the system they point to. If it is a misfire, this inspection is where we start. ### Is it safe to drive with a flashing check engine light? It is best not to. A flashing light usually means a severe misfire, and unburned fuel can overheat the catalytic converter. Drive gently and book soon. ### Should I replace all the coils at once? Not necessarily. We test each one. If the vehicle is at high mileage and the coils are hard to reach, we explain the trade-off on the estimate. --- Call (909) 608-7699 or visit https://route66autorepairshop.com/contact for a written estimate.