Why does my Chevy Blazer misfire at 2500 rpm?

A visual inspection showed that new spark plugs, spark plug wires, ignition cap, and rotor have been installed. Further information from the customer indicated that the truck misfired the worse in drive, not overdrive, at light to normal cruise around 2000 rpm to 2500 rpm. The next test drive indicated that he was right and it was very repeatable.

Can a 4 cylinder engine misfire on a 3 cylinder car?

If your 4-cylinder engine is misfiring on one cylinder, it may sound like a three-cylinder engine. If your car’s sound is extraordinary, it’s most likely misfires on every cycle that you can hear. So, when you suspect that your engine is misfiring, where should you start looking for the problem?

What are the most common signs of engine misfires?

The most common situation to notice misfires is on high gears, low RPM, and the accelerator to the floor. Rough acceleration is a typical sign that your engine is misfiring.

What do I do when my Chevy truck misfire?

I can put the trans in drive, hold my foot on the brake, and slightly rev the engine to 1000 rpms, and the cutting out is very noticeable and I can watch the tachometer jump around with each jerk. While driving, the tachometer bounces with the misfire.

Is there a code for cylinder 4.3 misfiring?

With the computer conected we monitored the live data and were recordeing most of the misfires in cylinder 6, 4, 2 with an occational misfire on 5. We had no codes recorded in the ECM but the fuel trims were way off.

What kind of engine does a Chevy Blazer have?

Although this case study is about my neighbor’s 1995 Chevy Blazer with a CPI equipped 4.3L engine, the info easily applies to any CSFI ‘Spider’ equipped 4.3L, 5.0L, and 5.7L equipped GM vehicle.

Are there any problems with the Chevy 4.3 Vortec engine?

The 4.3 Vortec engines made from 1996-2002 (L35 and LF6) have been reported to have engine knock problems. In a properly functioning engine, fuel burns in even pockets instead of all at once. The pockets burn in even timing, in sync with engine cycles. Engine knock occurs when the fuel burns unevenly and out of sync with the engine cycles.

Where is the O2 sensor in the exhaust manifold?

Fig. 2: Location No. 1 — Typical O2 Sensor located in the exhaust manifold Fig. 4: Location No. 3 — Exhaust collector (where more than 1 pipe joins together)

Why does my downstream O2 sensor show Bad readings?

The downstream o2 sensor’s job is to monitor the catalytic converter. Most mechanics will often say it’s the o2 that is shot when it is actually the cat. When the cat is restricted, the downstream o2 will show bad readings. Understanding downstream and upstream, LTFT (long term fuel trim and STFT…

What causes hesitation and surging on Blazer 4.3L?

Fix Hesitation and surging on Blazer 4.3L If you have Hesitation and surging on Blazer 4.3L and it’s driving like a dog—poor acceleration, hesitation, or a surge and you suspect a fuel problem, you may be partially right.

What kind of idle does a 1998 Chevy Blaz have?

Rough idle, surging, and hesitation – 1998 Chevrolet Blaz… Idles rough, worse under load and surges at times. Rpm varies at constant speeds (occasionally), hesitates when trying to pass a vehicle or speed up. doesn’t shift from 3rd gear to overdrive sometimes when hard accelerating, until I release the accelerator.

Why is my Blazer 4.3L driving like a dog?

If you have Hesitation and surging on Blazer 4.3L and it’s driving like a dog—poor acceleration, hesitation, or a surge and you suspect a fuel problem, you may be partially right. But before you start replacing really expensive components like the fuel pump, try this: Disconnect the electrical connector to the MAF sensor and take it for a drive.

What causes acceleration in a 97 Chevy Blazer?

97 chevy blazer 4.3 idles great but upon acceleration it starts to surge, changed just about everything, fuel pump,cap rotor, wires, plugs distributor injectors, crankshaft, cam, throttle pos. sensor, tried new computer, at a loss starts right up and idles great, take in down the road and starts surging. Exhaust?

What causes a Chevy 350 to backfire constantly?

The air intake boot or tube transfers air from the mass air flow sensor into the throttle actuator and then into the engine. If there is a problem with these parts such as a tear or rip it will allow un-metered air into the engine which the computer will see via the oxygen sensor which in turn will deliver less fuel creating a lean condition.

What happens when an engine misfires under acceleration?

When an engine misfires under acceleration/when the throttle is pressed, it’s not only bad for the engine, but it can be particularly dangerous for everyone on the road. Misfires can happen when a vehicle is under load while accelerating. This causes slow or sluggish acceleration and your vehicle may have trouble getting up to speed.

Why does my Chevy 350 backfire when I let off the gas?

If it backfires when you let off the gas peddle it has air getting into the exhaust, either an exhaust gasket or cracked manifold before the catalytic converter or the emission control’s Air Injection system. The air injection check valves (STANDARD MOTOR PRODUCTS PT#AV7) are common failure parts.

What causes a random cylinder to misfire in a Chevy?

P0300 Chevrolet Possible Causes. Faulty spark plug (s) Faulty ignition coil (s) Clogged or faulty fuel injector (s) Intake air leak. Fuel injectors harness is open or shorted. Fuel Injectors circuit poor electrical connection. Ignition coils harness is open or shorted.

What does misfire on P0300 Chevy mean?

P0300 CHEVROLET Meaning When a misfire occurs, engine speed will fluctuate. If the engine speed fluctuates enough to cause the Crankshaft Position (CKP) sensor signal to vary, the Engine Control Module (ECM) can determine that a misfire is occurring.

Can a lack of spark timing cause a misfire?

Lack of proper spark timing can cause a different problem, One or more of the cylinders may misfire. That is to say combustion may be disrupted. You will feel, and maybe hear, this as a brief stutter in the engine.

What to do if your Chevy truck misfires?

The truck will start and idle fine however as soon as you feed a little gas it starts to miss. Giving it even more gas is either covering up the misfire or it is clearing and seeems to run better. I’ve just replaced cap/rotor wires and plugs.

Why did my Chevy S-10 misfire in the morning?

My morning misfire was caused by a bad intake manifold gasket (a very common problem with most gm models around 2000 model year. Caused by crappy dexcool coolant ). After sitting overnight a small amount of coolant would get into right rear cylinder. It would miss for a bit and then run fine. Doesn’t have to be leaking a lot either.

What’s the misfire code on a 1998 Vortec?

Can someone please help with what I should check next, I have a 1998 Chevy K1500 5.7 Vortec with a misfire, P0300 code for 3 months. runs a little rough, while driving under normal conditions it sputters, hesitates, and also will backfire, under heavy acceleration no noticeable skip, no sputters, and does not hesitate or backfire.

How long does a 2000 Chevy Blazer last?

All go out around 100,0000 mi. I knew of these common problems before purchase. If kept in good order l, she should last around 250,000 mi. Plenty of power if you increase air flow. Fits all three grand kids and daughter with no problem on small adventures. Fits all of my tools for work.

How to troubleshoot a misfire ( GM 4.8L, 5.3L )?

Engine Mechanical: Misfire Troubleshooting. You can find this tutorial in Spanish here: Cómo Diagnosticar y Resolver Una Falla en Cilindro (GM 4.8L, 5.3L, 6.0L) (at: autotecnico-online.com ). The core symptom of a misfire is rough idle.

Is the Chevy Blazer a good car to buy?

Goes & tows everything I need it to when and where I need it to. Cheap to fix when it does break which is rarely. Loved everything about that truck. Good all around vehicle. Not as roomy as it looks. Good deal for what I paid for. I replaced the radiator, fuel pump, and intake manifold gaskets. All go out around 100,0000 mi.

Why does my Chevy Blazer have no power?

If not that code then your problem is most likely the cheap plastic distributor that GM installed for that year. Take off that expensive cap and see if the shaft jiggles. It is better to remove the distributor to inspect it. AutoZone sells a lifetime warranted Distributor for about $90.

Why does my Chevy Blazer engine bog down when I hit the gas?

Take it to a good local mechanic (not a dealer) and see if this is one problem. My Blazer bogs down when you hit the gas and has trouble starting. We have replaced the MAF sensor, plugs, rotor, cap, plug wires, and fuel filter. The fuel pressure is at 50psi when idling and 64 wot when driving.

What makes a rough idle a misfire condition?

What complicates a rough idle/misfire condition is having the PCM not register any specific misfire codes. In my neighbor’s Blazer, the PCM wasn’t even registering a P0300, but it was obviously running very rough (at idle that is).

How can I tell if my spark plugs are bad?

Attach a spark tester to the wire and to an engine ground. Crank the engine and check for a good spark at the spark tester gap. A good spark will be blue-white and will be plainly visible in daylight. If a good spark is present, the problem is probably not in the ignition system.

Can a bad spark plug cause an engine to missfire?

If the engine starts to buck, stumble or missfire you could have a ignition related problem like a spark plug wire or ignition coil. if the engine bogs down and looses power you probably have a lack of fuel pressure or fuel volume problem with the fuel pump.

What causes a spark plug wire to burn?

This causes an increase in the voltage required to fire the spark plug, which could damage the ignition coil as well as the spark plug wires. Heat damage – Engine heat can burn wire insulation and boots. A damaged boot can impede proper spark plug wire seating and performance.

Why is my Chevy Vortec 4300 V6 leaking fuel?

In the L35 and LF6 engines, the spider injectors are known to leak at the pressure regulator and at the supply and return lines due to a design fault. Outside of leaking fuel onto the exterior of the engine itself, it can cause excess fuel to get sucked into the engine.

Why does my Chevy Blazer misfire at 2500 rpm?