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Nelson Performance

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United States
San Antonio, TX
Nelson Performance

GM LS & LT Performance, Diagnostics & Tuning LSx Performance Specialists
Trucks/cars/suv
GO FAST! In house dyno, tuning, custom wiring, installation, parts.

HPTUNERSD - FAST XFi - Holley EFI

Please contact Nelson performance at 210-626-0278 or at [email protected] for any orders or detailed pricing questions/ inquiries.

09/25/2026

🔥 LS SWAPPED. NOW IT’S TIME FOR SOME UPGRADES. 🔥

The LS swap is already done — but this truck isn’t finished yet. 😎

It’s back in the shop and the next round of work is getting started:

💨 Turbo setup
⚡ Chassis harness
🔧 Maintenance & repairs
👀 And a few more things along the way...

This is one of those builds we’re going to take you along for. We’ll be posting updates as it progresses — from the install and wiring to getting everything sorted out and ready to run.

👉 FOLLOW THE BUILD. You’re going to want to see where this one ends up. 🔥

09/24/2026

🔥 OLD SCHOOL. LS POWER. 🔥

This 1955 Chevy 2-door sedan may have classic looks, but there’s a whole different story under the hood. 😎

The customer built this beauty and brought it to Nelson Performance for the tune — and there’s plenty here to work with! 💻🔥

⚙️ THE BUILD:
🔴 1999 LS engine
🔴 MADD MAXX camshaft
🔴 Ported 243 heads
🔴 LS6 intake
🔴 Stock LS3 exhaust manifolds
🔴 3" exhaust
🔴 3,000 RPM stall converter
🔴 3.08 gears
🔴 4L60E transmission

There’s just something about taking a 70+ year-old Chevy and giving it modern LS power. Classic body, modern drivetrain, and a combination built to be DRIVEN. 💪🔥

CUSTOMER BUILT. NELSON TUNED. 💻🏁

What do you think — would you keep the classic look with LS power, or stay old-school under the hood too? 👇👇

📍 Nelson Performance
📞 210-626-0278
🌐 NelsonPerformance.com

09/23/2026

🔥 MODS DONE. NOW MAKE THEM WORK TOGETHER. 🔥

This 2012 Silverado came to us already equipped with some upgrades:

💥 LT Headers
💥 Cat Delete
💥 Cold Air Intake
💥 Federal Commander Throttle Body Controller

Our job? THE TUNE. 💻⚡

Once you start changing airflow and exhaust, the calibration needs to match the combination. We dialed this Silverado in to get everything working together and make the most of the modifications already on the truck. 👊🔥

Already modified your truck and ready to get it tuned right? That’s where we come in. 😎

📍 Nelson Performance | San Antonio, TX
📞 210-626-0278
🔧 TUNING. DIAGNOSTICS. RESULTS.

🔥🏁

09/22/2026

👀 LOOKS FINE… UNTIL YOU LOOK CLOSER.

This is the throttle body harness on a 2003 Silverado we’re currently diagnosing.

At first glance, you may not see anything alarming. No bare copper. No obviously broken wires. But look at how sharply those wires have been folded and stressed right at the connector.

That matters.

A wire can be damaged inside the insulation without looking broken from the outside. That can create an intermittent connection, excessive resistance, or an open circuit—and lead to throttle-related faults that can be frustrating to track down.

🔧 This is why diagnostics isn’t just about reading a code and replacing the part named in the description. Sometimes you have to follow the circuit, inspect the harness, and look closely at what the wiring is telling you.

On this Silverado, the compromised throttle body harness is being replaced as part of the repair.

The problem isn’t always obvious. Sometimes you have to know where to look. 👀

📍 Nelson Performance
🔧 Tuning • Diagnostics • Performance

09/21/2026

⚡ ONE SHORT. MULTIPLE FAILURES.

This 2003 Silverado is a perfect example of why electrical diagnostics can be a process. 🔍

During diagnosis, we traced the problem back to the camshaft position sensor wiring — and the picture tells the story. 👀 The wiring was damaged with bare conductors exposed, allowing the circuit to short.

The bigger problem? This circuit has a direct 12V power supply without fuse protection at this point. When it shorted, the damage didn't necessarily stop at the wiring.

We found multiple components affected, including the ECM, Throttle Actuator Control (TAC) module, and accelerator pedal position sensor/assembly.

This is exactly why we don't just replace the first module associated with a code and call it fixed. A failed component can be the result of the problem — not the cause.

Finding the source matters. Otherwise, you risk replacing expensive electronics while the original problem is still sitting there waiting to damage them again. 🛠️

And as we continued inspecting this Silverado, this wasn't the only compromised wiring we found. More on that one later. 👀

📍 Nelson Performance | San Antonio, TX
🔧 Tuning. Diagnostics. Results.

09/20/2026

🔧 TECH TIP SUNDAY 🔧

WHY DOES MY ENGINE IDLE ROUGH?

A rough idle is one of those symptoms that can have a LOT of different causes. Your engine may shake, stumble, surge, feel like it wants to die, or just not sound quite right while sitting at a stop.

So what causes it? 🤔

⚡ IGNITION PROBLEMS
Worn or fouled spark plugs, damaged plug wires, or a weak ignition coil can cause a cylinder to misfire—especially at idle.

⛽ FUEL DELIVERY ISSUES
A dirty or failing injector, incorrect fuel pressure, or another fuel-delivery problem can keep a cylinder from getting the fuel it needs.

💨 VACUUM OR INTAKE LEAKS
Unmetered air entering the engine can throw off the air/fuel mixture and create an unstable idle.

🔌 SENSORS & ELECTRICAL ISSUES
MAF, MAP, throttle-body, wiring, connector, and other electrical problems can all affect how the engine runs.

🔧 MECHANICAL PROBLEMS
Low compression, valve or lifter problems, valvetrain issues, or other internal engine problems can also show up as a rough idle.

💻 CALIBRATION
Yes, the tune can affect idle—especially on a modified vehicle with a larger camshaft, injectors, airflow changes, etc. But the tune cannot repair a mechanical or electrical problem.

And that’s the important part. 👇

Same symptom. Many possible causes.

A trouble code gives us information, but it doesn't necessarily tell us which part to replace. Proper diagnostics means testing the system, finding the actual cause, and fixing the problem instead of guessing and throwing parts at it. 🎯

That’s how we approach diagnostics at Nelson Performance.

🔴 Follow Nelson Performance for more Tech Tip Sundays! We’ll keep breaking down what’s happening under the hood—and why. 🔧🏁

09/18/2026

🔧 GOOD THINGS TAKE TIME.

Remember this Camaro from earlier this week? It came to us for a tune, but we quickly realized a tune wasn’t the fix.

We started with a misfire on cylinder #7. Testing led us to a bad spark plug and damaged injector wiring. We repaired both, retested… and kept digging. 🔍

That’s when we started seeing additional random misfires.

Next step? We pulled the injectors and found they were all dirty. They were cleaned, serviced, reinstalled, and the car was tested again.

Better — but we still weren’t done.

Misfires remained on cylinders #1 and #4, and further testing led us to damaged ignition coil wiring harnesses. New harnesses are on the way, and once they’re installed, we’ll test it again. 🛠️

👉 This is what diagnostics actually looks like.

Sometimes there’s one problem. Sometimes there are several problems stacked on top of each other. You diagnose what the vehicle is telling you, make the necessary repair, retest, and then determine what comes next.

We don’t want to guess. We don’t want to throw parts at a vehicle. And we definitely don’t want to try to tune around a mechanical or electrical problem.

Diagnose. Repair. Retest. Repeat when necessary. 💪

That’s how we get to the actual fix.

📍 Nelson Performance | San Antonio, TX
🔧 GM LS/LT Performance • Diagnostics • Tuning

09/17/2026

SHOP GEAR IS STOCKED UP! 👕🔥

Jo Ann got us stocked back up on Nelson Performance gear!

We’ve got several designs and sizes available here at the shop—including our new NP logo and San Antonio/Texas designs. ❤️🤍💙

See one you like? Drop your size in the comments or message us for pricing and availability!

Available at the shop while supplies last.

📍 Nelson Performance | San Antonio, TX

Crafty Babes SA

09/16/2026

WHEN A TUNE ISN’T THE FIX… 🔧

This 2014 Camaro came to Nelson Performance for a tune — but before we start changing the calibration, the vehicle needs to be running right.

We found a misfire on cylinder #7. During diagnostics, we traced the problem to a bad spark plug and damaged injector wiring.

🔧 Repaired the injector wiring
⚡ Replaced the faulty spark plug
✅ Verified the misfire was corrected
💻 Then we could move forward with the tune

This is exactly why we diagnose problems before trying to tune around them. A tune can improve how a properly functioning vehicle runs — but it isn’t a repair for a mechanical or electrical problem.

Fix the problem. Then tune the car. 💪

📍 Nelson Performance | San Antonio, TX
GM LS/LT Performance • Diagnostics • Custom Tuning

09/15/2026

🔥 2024 CAMARO — SUPERCHARGED. 🔥

This one got a serious upgrade. We installed a Magnacharger TVS2650 Supercharger Kit along with the supporting mods to make the whole combination work together:

💥 LT4 fuel system upgrades
💥 Flex Fuel Kit
💥 Katech 103mm throttle body
💥 Roto-Fab Big Gulp intake
💥 160° thermostat
💥 Custom Nelson Performance tune

And like most real builds, everything didn’t just bolt together perfectly and magically work. 😂 The intake needed to be ported to properly accommodate the 103mm throttle body, so we handled it.

We also caught a slight wobble in the harmonic balancer pulley supplied with the supercharger kit. Magnacharger was excellent to work with—once they saw the issue, they immediately sent a replacement via 2-day air. New pulley went on, problem solved. 👊

That’s part of building modified cars. Small issues happen. The important part is catching them, correcting them, and making sure the car leaves right.

Now this Camaro is buttoned up, tuned, and ready to enjoy some BOOST. 😈🔥

Address

10034 Roosevelt Avenue
San Antonio, TX
78214

Opening Hours

Monday	9am - 5:30pm
Tuesday	9am - 5:30pm
Wednesday	9am - 5:30pm
Thursday	9am - 5:30pm
Friday	9am - 5:30pm

Telephone

+12106260278

Website

http://www.nelsonperformance.com/

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