1999 chevy tahoe misfire at idle rough idle, check engine light,codes say #3 misfire, lean bank, both sides. Feb 1, 2011 · Greetings, My ride: 1997 Tahoe 2 door 5. Aug 27, 2018 · P0304 Definition: 4’th Cylinder- Misfire Detected 4’th Cylinder P0304 is a cylinder-specific misfire code, meaning only your Tahoe’s fourth cylinder has a misfire. 7 5-speed). I Jul 5, 2012 · I've got a friend with a 1999 Tahoe with a 5. 3 misfire only at idle? Discover common causes, troubleshooting tips, and effective solutions to fix your engine's misfire and restore smooth performance. When I finally found the table for idle in gear I realized how obvious it was. Pretty much behaved as I described although after driving for hours and stopping I had a couple of instances in gear at a stop that felt like the lock up was trying to engage or remain engaged even though I came to a stop. 7 equipped with the stock SFI system. Mar 2, 2024 · Hey all, I've been grappling with a random misfire for a while now. The pcm has not thrown a code since I cleared it the first time but on the live misfire data I can see it misfiring. Eased it on home, hooked up VCM Scanner, and pulled the code: P0300 Random. 7L. You can use the tests in this article to test and diagnose: A bad ignition control module (ICM), or 1999 tahoe, 350 135000 miles. The issue disappears when you give it more gas and the RPM's increase again. now that I have installed TFS cam Oct 10, 2020 · Anyways, if you're having a misfire at idle, P0300, P030x, definitely suspect the manifold gasket. Sep 12, 2012 · i recently bought a 99 tahoe 4WD 5. Shows - Chevrolet 1999 Tahoe question Jul 10, 2014 · It will loose power when at speed and when accelerating. I presume the ECU is recording a knock? The ECU tells the pump when to turn on via a relay (at least that’s how my Porsche works). I'm somewhat capable of performing most routine maintenance, but chasing misfires isn't my something I do everyday. The tick went away so good on that but I am still seeing a P307 after the engine idles for more than 5 minutes. It's and OBD2 code and stands for: P0305: Misfire Detected → Cylinder 5 P0305 is certainly a cause for concern, and should be considered a threat to the drivability your Tahoe. Aug 27, 2006 · Friday my 99 Tahoe was fine. Sep 8, 2019 · It can be very jarring when your Chevy Tahoe shakes when idle. 135, 000 mi. Started misfiring, scan said misfire #5, Misfire is felt through the whole RPM range. Rough Idle Tests. I have a scanner so i can erase the code, and the car will run maybe a couple minutes and Aug 16, 2010 · Why? Because anything from a bad COP Coil to low engine compression can cause a misfire. Took it to the store yesterday and noticed a misfire on the way home at around 1K RPM then got the flashing CEL. i changed the plugs, wires Mar 24, 2016 · OK so I have a 1999/2000 Tahoe 149,000 5. About two weeks ago, the vehicle began to misfire and illuminated the CEL. 7 vortec With a cylinder 7 misfire. It only occurs at idle - as soon as you touch the throttle, it's smooth as silk and performs perfectly. 3 quickly and easily. Jul 7, 2010 · You can test for a intake leak by spraying the intake area with water (idle will faulter if it draws water in), or use brake cleaner (idle will raise when fluid gets drawn in). Random Misfire Tests. I have a 2000 chevy tahoe z71 with the 5. Mar 5, 2013 · Drove the Tahoe there and back from Ohio. It is throwing a p0300 Random Misfire code. As you can see in the pictures above, even some aftermarket parts were just plastic and silicone. 1999 chev tahoe, 5. At idle for some reason factory uses 18* in gear. 7 liter. Initially I Nov 21, 2024 · Rough Engine Idle and Misfires When Cold on GM 4. Aug 30, 2019 · If you own a Chevy Tahoe and it's idling rough, you may be feeling frustrated. Jun 6, 2010 · This tutorial will help you determine the cause of a misfire or 'no-spark, no-start' condition on your GM car, pickup, mini-van, van or SUV equipped with a 4. 7 Vortec 130K miles. Apr 23, 2010 · I've been experiencing some random misfire lately on my '02 5. 0L and 5. One morning it started running rough sputtering and misfiring so I told her to park it until I have a chance to look at it. The misfire will be almost immediae. the trouble code is 0302 Sep 13, 2024 · Truck is well-kept and serviced. (To replace my horribly rusted 95 k2500 5. The tests are explained step by step to make the whole diagnosis and troubleshooting as painless as possible. 7 vortec, currently at 322k miles. at first it had a cylinder 6 misfire. Jan 31, 2013 · I have a misfire that cannot be diagnosed!!!! 1999 5. (Fuel filter was changed 6 months ago along with a check of the fuel pressure, new factory pump 3 Diagnostic Tip for Misfire, Chirp, Squeak, Squeal or Tick Noise, Malfunction Indicator Lamp (MIL) Illuminated - DTC P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307 and/or P0308 Set Jun 1, 2023 · I have a 1999 Tahoe with the 5. The issue isn't constant, but seems to be more pronounced if I'm going uphill and I'm light on the throttle I'll get a vibration, followed by the check engine light. 0L engines is common, and getting harder to diagnose. Aug 22, 2019 · Hey there, I found a great deal on a 91 K2500 5. This trip used Update: This issue has been resolved, and confirmed 100% the cause of my idle misfire was the ignition timing setting "in-gear". 3L, 5. 7 tahoe. Jan 2, 2011 · My gf has a 1999 OBS Tahoe with a 5. Learn how to diagnose and resolve idle-specific issues for your Chevy 5. Compression is good on all cylinders. New plugs, wires, cap/rotor Aug 3, 2013 · Hello all, I recently have aquired a misfiring issue or what I believe to be a misfiring issue on my 99 5. You can feel it shake. 3 Sierra. no improvement. Bought it with a very slight misfire on cylinder 4. Before you can even diagnose P0304 in your vehicle, you need to find the fourth cylinder’s location. The new (to me) truck has a misfire problem that I haven't yet been able to figure out. advised here to replace ecm, done, and flashed to vin. The misfire count Jan 24, 2022 · 2003 Yukon XL Denali LQ4 VIN "U", 209K, stock tune. I have replaced all spark plugs (AC Delco), spark plug wires (summit), distributor cap & rotor (AC Delco), coil, driver side 02 sensor, fuel filter, fuel pump 1 year ago, and coolant temperature sensor. In order to test for this condition, spray the wires with water and with the engine running, watch for spark to jump from the wires. the plug is carbon fouled and the only one that is. 3L, or 5. It all started a few weeks back when I was towing one of my enclosed trailers on a 3 1/2 hr trip (one way). We figure a Jun 7, 2018 · I have a scan tool, I can see the misfire counter add up on cylinder 5, and it seems to be only at an idle. had rough idle and pinging. 550rpm and 12-13* of timing gave it a silky smooth idle tone, very comfortable with OEM camshaft LM7. Armed with the knowledge of what can cause a misfire, rough idle condition and a specific testing strategy, you can easily find out what component is the one that has failed. replaced spider injectors and regulator, newer fuel pump, replace all plugs, #3 was very fouled, new wires, cap, rotor. 3L, 223k miles, no codes. Jul 18, 2011 · Well not even half way down my street the truck started running fine, no rough idle, no hesitation, no stumbling, nothing. The most common reasons a vehicle shakes when idling is a misfire or bad motor mount. An ammco shop Customer: Hi. Ignition and fueling have been gone through. Saturday morning when I cranked it up the idle was between 2200 and 2400 rpm. No codes to indicate a misfire or pressure issue Dec 11, 2012 · Well lets see imma start from the top I got my tahoe in august of last year and all the maintenice was not tooking car of so far Ive replaced distrubutor cap and rotor spark plugs (not autolites)LOL! wires fuel pump fuel filter updated spider injector seafoamed it trans fluid exchange coolant Mar 6, 2024 · 5. Runs fine above 800 RPMS, but when it goes to an idle and the RPM's comes down it runs really rough. It will start normally and idle fine (with a barely noticeable misfire). compression all Feb 4, 2020 · Mileage may suffer as well when your Tahoe has P0308 as well. It Mar 18, 2018 · No description has been added to this video. I usually use about $150-160 worth of gas on the 7 hr trip. May 19, 2009 · Something is causing a low pressure that is allowing the engine to go lean and predetonating/misfiring. clean mass air sensor. It started as a P0303 code, now it's the random p0300. replaced spider injectors with rebuilt and tested complete 1997 tahoe 5. If the misfire occurs when the weather is damp, the problem could be due to worn plug wires. Historical issues - intake gasket replaced twice < 20,000 miles. 0L, or 5. So i plugged the scan tool into it and got a pending cylinder 1 misfire code, but everything else was ok, according to the scan tool. It’s only noticeable at idle causes a little vibration. We've lined out some of the most common causes below. - very rough idle, makes the vehicle shake - throwing a 305 code (misfire on cylinder 5) - a rattling noise when I get on the Aug 18, 2012 · Testing a Misfire Code (P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307, P0308) on GM 4. more Oct 6, 2018 · P0305 is a fairly common trouble code with the Chevy Tahoe. Since I didn't have a specific cylinder code, I Oct 16, 2019 · Hello, I have a 2000 Tahoe z71 classic (2000 model year, 1999 body style) that I'm having a misfire issue on. 3L, 6. 7L engine. In this article, we'll look at some of the most common causes of a rough idle in the Tahoe and how to fix the problem. Didn't drive it for about 4 years or so until last year. My Issue: Getting a random misfire P0300 at higher speed( over 75 MPH) or when the engine is under load, uphill or passing with AC on. 7 vortec. Nov 26, 2020 · I purchased it knowing there was a misfire on cylinder 4. Table of Contents Diagnosis Causes Shakes In this video we have a look at a Chevy Tahoe that came in with a customer complaint of high idle and misfire after the vehicle warms up. plug is getting spark and 2001 astro van rough idle it was running fine now i have a rough idle. Getting and engine shudder as well flashing SES light which then goes solid. 7 automatic and bought it. 7 engine with 211K miles. The check engine light (CEL) may also come on, with codes P0300, P0171 and P0174. . Can someone share some advise on how to test Jun 28, 2009 · #6 Cylinder Misfire, Rough Idle but smoothes out after running down the road and Idles fine afterwards. 8L, 5. On “V” configuration engines, it’ll usually be the second cylinder on the head further away from the front of the Mar 18, 2022 · I had hoped the collapsed lifter was the cause of my misfire on cylinder 7 P307 but nope . If your Tahoe has this problem, many issues can cause it. It has had cylinder 7 misfire, random misfire, rich, and 02 sensor codes. But, as the engine warms up, the engine misfire or rough idle tends to go away, which seems confusing. I don't know much of the history as its hard to track down its previous owner. Well, troubleshooting and solving a misfire doesn't have to be hard. My engine has been rebuilt because of a dead #7 cylinder at 167800 miles. Here's a list of what I replaced: plus and wires, cap and rotor, fule pump and filter, mass air flow sensor, spider injection (upgraded version), temp Guage sensor, upper 02 sensor, purge vent valve sensor, air filter, knock sensor. The nice thing about P0305 is that it's a cylinder specific trouble code, Feb 10, 2010 · 1999 Suburban K1500 5. I have checked all hose connections but am at a loss. An important thing to understand when finding the location of cylinder 8 is that it’s going to be the eighth cylinder in the firing order. I suspect I might have a coil that acting up. About a year ago I had a bad misfire at idle on cylinder 3 and after a leak down test I found that the exhaust valve was leaking way beyond spec. Jul 18, 2010 · To refresh my truck's info since I know no one would remember; '99 2WD, 4 Door LT, 161,000 miles Owned since new, taken well care of overall. Multiple Sep 26, 2025 · Experiencing a Chevy 5. 7getting a misfire on #1. I have changed the plug wire, spark plug wire for that cylinder and the distributor rotor. We hooked it up to the computer with my scan tool and saw a lot of misfires. As, GM V8 engines are prone to a rough idle, and engine misfire when cold. Aug 20, 2014 · I recently acquired a 99*Tahoe. Changed the following: Plugs, Wires, Cap, Rotor Air Filter. Cylinder 2 misfire comes and goes. smooths out under load, but lacks power on hills. To start off here's a list of some problems with it. The customer already replaced TPS, IAC motor and spark plugs. I moved plugs, plug wires, coils and injectors to other cylinders, but the misfire at idle stays on cylinder 5. 7 vortec from a friend and its having some issues. Chevy Tahoe P0308 Definition P0308 is a cylinder specific misfire code, which means that cylinder 8 is misfiring and causing it. 7 138k. e27 ibo oblzja egy1ed cbor 5w8two 1zep apsaqs yqrv0 5bhply