Why does my Mazda B2200 miss going uphill or have dead spots when I accelerate?

Short answer: Two B2200 owners on Car Talk found simple causes. One truck that missed going uphill after a head job turned out to have the ignition timing slightly off, even though it looked right at first. Another truck with two dead spots while accelerating had loose venturis inside the carburetor (the small round parts in the carb throats), which leaned out the mixture. Re-check timing carefully, then replace the fuel filter and check for an exhaust restriction before you go into the carb.

Symptom: The truck runs fine on level ground but starts missing when you load it, like going up a hill. Or it stumbles at two spots in the rev range while you accelerate.

What to check first

1. Re-check the ignition timing carefully with a timing light, especially after engine work. Have a second person look.
2. Replace the fuel filter and, if you can, put a pressure gauge on the fuel line.
3. Check for an exhaust restriction like a clogged converter (a vacuum gauge test is easiest).
4. Check plugs, wires, cap and rotor.
5. On carbureted trucks, look inside the carb for loose parts if it still has dead spots.

Likely causes

1. Ignition timing slightly off. The fix for the 1992 truck that missed going uphill after a head job.
2. Loose carburetor venturis. The fix for the 1991 truck with dead spots. They worked loose and leaned out the mixture.
3. Clogged fuel filter or weak fuel supply. A member's first suggestion for missing under load.
4. Exhaust restriction. A plugged converter or muffler can cause a miss under load.

What it usually costs

No owner posted prices in these threads. Timing adjustment is labor only, and a fuel filter is cheap. A carb rebuild or replacement costs more.

Is it safe to keep driving?

A miss under load isn't usually an emergency, but a truck that loses power going uphill or merging is risky. A flashing check engine light or strong fuel smell means park it. Verify with a mechanic.

DIY or shop?

DIY-friendly. Timing, the fuel filter and plugs and wires are basic jobs. Taking apart a carb takes more patience but is doable.

Recalls, bulletins and complaints in plain words

• Recalls: NHTSA lists no recall for engine or fuel problems on the Mazda B-Series trucks in the model years we could check on 2026-10-27 (the recall lookup returned an error for 12 model-year queries). Check your VIN at nhtsa.gov/recalls. If your car is part of a recall, the dealer fixes it for free.
• Plain words: No recall we found matches this problem, so it's a normal repair, not a free recall fix. Still run your VIN, since other recalls may be open.
• NHTSA complaints: 9 keyword-matched complaints for Mazda B-Series trucks (B2200) 1986–1993 (of 36 unique complaints queried, NHTSA complaints API by model year, queried 2026-10-27; keywords: stall, dies, no start, cut out, idle, miss, hesitation, power, carburetor, backfire, timing, rough) (NHTSA returned no complaint data for 8 model-year queries). This counts complaints that mention these words. It is not a defect finding.

What owners report

• In 1992 mazda b2200 problems on Car Talk, an owner had done the water pump, oil pump, timing belt and a head job, and then the truck missed under load uphill but not on level ground. Members suggested timing, plugs and wires, the fuel filter with a pressure gauge, and an exhaust restriction check. The owner came back to say it was fixed: the timing was off just a little, even though it had looked right.
• In Fixed my 1991 Mazda B2200 truck! on Car Talk, an owner who'd had two dead spots while accelerating opened the carburetor and found the venturis had worked loose, so they weren't feeding the right amount of fuel. Tightening them fixed it.

Quick tip

After any timing belt or head job, re-check timing before chasing other parts. Being off just a little is enough to cause a miss under load.

Vehicle focus: 1986–1993 Mazda B2200 pickup.

Safety / mechanic note

Keep hands and timing light leads away from the fan and belts with the engine running. Verify with a mechanic.