HOW MUCH IS DIESEL RIGHT NOW IN PUEBLO, CO?

Three sources, in order of how useful they are for Pueblo specifically:

• GasBuddy, filtered to diesel, zip 81003–81008 — station-level, updated by users, usually within a few hours of reality.
• AAA Fuel Prices, Colorado → Pueblo County — a clean daily county average. Better for "is this normal?" than for "where's the cheapest pump."
• EIA Weekly Retail Diesel, Rocky Mountain (PADD 4) — published Mondays around 5 p.m. ET. This is the wholesale-driven regional signal; Pueblo retail typically tracks it within 10–25 cents.

If a Pueblo station is more than about 30 cents off the county average, it's usually either a card-lock/fleet-only pump or it hasn't repriced since the last rack change.

Colorado sits in PADD 4, the smallest and most isolated refining district in the country. Rocky Mountain diesel routinely runs 15–40 cents above or below the national average depending on refinery turnarounds in the Denver and Salt Lake area — and when a single unit goes down, there's very little pipeline slack to absorb it. A hiccup that would move Gulf Coast prices 3 cents can move Front Range diesel 25 cents in a week.

Taxes stack on top of that:

• Federal excise: 24.4 cents/gal on diesel vs. 18.4 cents on gasoline — diesel starts 6 cents behind before anything else happens.
• Colorado state excise: 20.5 cents/gal on diesel (gasoline is 22.0 cents).
• Colorado's road usage fee, phasing in since 2022 and stepping up annually toward roughly 8 cents/gal by the early 2030s.

Then there's the seasonal blend. From roughly November through March, Colorado suppliers cut #2 diesel with #1 (kerosene) to keep it from gelling — Pueblo's January average low is around 15°F, and untreated #2 diesel starts clouding near 14°F. A 30% #1 blend carries about 2% less energy per gallon, because #1 holds roughly 128,000 BTU/gal against #2's 137,000. Your winter MPG drop isn't imaginary and it isn't your truck's fault.

Price per gallon is the number people search. Cost per mile is the number that empties the account. At $3.90/gal:

• A ¾-ton diesel getting 17 MPG unloaded costs 22.9 cents/mile in fuel.
• The same truck at 14 MPG — a realistic number with dirty injectors, a loaded DPF, or 8 psi low on all four tires — costs 27.9 cents/mile.
• Over 20,000 miles, that 3-MPG gap is $1,000/year, more than the price of most fuel-system repairs we do.

Add the diesel-specific overhead nobody quotes at the dealership: DEF runs about 2–3 gallons per 100 gallons of diesel, so 1,200 gallons burned means roughly 30 gallons of DEF — around $100–$150/year at jug prices. Diesel oil changes take 12–15 quarts and run $130–$220 against $60–$90 for a gas half-ton. Fuel filters are $90–$180 every 15,000–20,000 miles and are not optional on a common-rail system.

> Fuel price is the number you can't control. MPG is the number you can — and on a diesel, three lost MPG costs more per year than the repair that caused it.

This is the section that costs us work, and we'd rather say it than have you find out at 90,000 miles.

At today's spread, diesel does not pay for itself on fuel savings. Run the math with diesel at $3.90 and regular at $3.15. A gas ¾-ton at 17 MPG driving 30,000 unloaded miles burns $5,559. The diesel version at 22 MPG burns $5,318. You saved $241 — and DEF ate most of it. The diesel option cost $9,000–$10,500 more up front. That payback period is not long; it doesn't exist.

Diesel wins on towing and duty cycle, not at the pump. Pull a 12,000-lb trailer over La Veta Pass (9,413 ft) or Monarch (11,312 ft) and the gas truck drops to about 9 MPG while the diesel holds 14. Across 30,000 towing miles that's $10,500 vs. $8,357 — a $2,143/year swing. If you tow, a diesel is the right tool. If your truck is a commuter that sees a trailer six weekends a year and covers 8,000 miles annually, you are paying a $10,000 premium and $150/year in DEF to save about $64 a year in fuel. Buy the gas engine.

Where we'll tell you to walk away from a repair:

• A $3,000–$5,500 full injector set on a truck with a $6,000 book value. We'll quote it honestly and then tell you it's a bad trade. Same with a $2,500–$4,500 turbo on a high-mileage unit that's also weeping coolant.
• A CP4 pump failure that sent metal through the rails. Correct repair is the entire fuel system — commonly $8,000–$12,000. On most trucks past 200,000 miles, that number ends the truck.
• Chasing a 1-MPG loss. Diagnosis runs $120–$180. If we find nothing but a slightly restricted filter, a 1-MPG gain at 12,000 miles/year is worth about $180/year — real, but not worth a $900 speculative parts job. We'll say so.
• "Fuel economy" additives and tuners. A bottle of cetane booster at $12–$25 does not return measurable MPG on a healthy engine. A tune that claims +4 MPG almost always achieves it by altering emissions strategy.
• DPF and EGR deletes. We don't do them. Federal penalties aside, a deleted truck fails Colorado's diesel opacity inspection, is difficult to insure a warranty claim against, and typically loses $3,000–$6,000 in resale value to any buyer who needs it to pass. If that's what you're calling about, we're not your shop.

One more inconvenient item: idling. A ¾-ton diesel burns roughly 0.5–0.8 gallons per hour at idle — $2.00–$3.10 an hour at current prices. Two hundred idle hours a year is $400–$620 burned going nowhere. No repair we sell fixes that. Turning the key does.

In rough order of dollars returned per dollar spent:

• Tire pressure. Running 8–10 psi low across four tires costs roughly 1–2% in fuel economy — about $60–$120/year at 15,000 miles. Free to fix.
• Fuel and air filters on schedule. A restricted air filter on a turbo diesel shows up as soot and sluggish throttle before it shows up on the trip computer.
• Injector condition. Dirty or leaking injectors are the single most common cause of a 2–4 MPG drop we see on 6.7L Power Strokes and 6.7L Cummins in the 120,000–180,000 mile range.
• DPF regen health. A truck stuck in frequent active regen can lose 5–8% economy. Short in-town trips around Blende and the Mesa Junction make this worse than highway running to Colorado Springs.
• Sensor drift. MAF, MAP, and exhaust temp sensors fail gradually. The truck compensates, economy slides, and no light comes on for months. This is exactly what [auto diagnostics](/services/auto-diagnostics-pueblo) is for.

If a light *has* come on, read [what a check engine light means in Pueblo](/blog/check-engine-light-pueblo) before you clear the code — clearing it erases the freeze-frame data that makes the diagnosis quick and cheap.

Diesel diagnostic at Iron Horse runs $120–$180, applied to the repair if you proceed with us. Fuel filter service on most late-model diesels is $90–$180. A full fuel-system inspection with injector return-flow testing is $180–$250 and takes about two hours. If the finding is "your truck is fine, your winter blend and your tire pressure explain the MPG drop," that's what we'll write on the invoice — and that's a $150 answer that saves you from a $2,000 guess.

We're in Pueblo and cover [Pueblo West](/areas/pueblo-west), Blende, Salt Creek, and Avondale. Before a long haul over the passes, the [summer pre-trip inspection](/blog/summer-pre-trip-inspection-pueblo) checklist is worth ten minutes of your time — heat, altitude, and grade are harder on a loaded diesel than the miles are.

Short version: budget $3.80–$4.00/gal in Pueblo this week, verify it live before you fill, and understand that the difference between 17 and 14 MPG will cost you more this year than the pump price will.