Vibration in engine, and lack of full power


Asked by Jun 12, 2015 at 11:59 PM about the Chevrolet C/K 1500

Question type: Maintenance & Repair

This 97 Z71 K1500 standard cab short bed step side with a factory steel cowl induction hood is a fine example in emerald green metallic. It was a truck that my son bought. After he ran it dry of oil, it became mine to settle his bill. The motor was to far gone to rebuild so I decided to buy a new GM Performance 350 CID L31-R 9.5:1. While I was at it I added a set of BBK shorty headers and a 1"throtle body spacer. While apart gasket matched exhaust ports and smoothed them out for better flow. Installed a new clutch and pressure plate. The 1st time I went to start it  stopped cranking. After all the checks you would normally make, battery, starter,   ect. I decided to pull the spark plugs and found that # 5 cylinder was full of gas. Drained the oil/gas, and squirted oil into #5. Pulled the top of the intake off laid rags in around the fuel injector and powered it up. The fuel regulator was leaking and the fuel ran down #5 runner. Replaced the regulator and put it back together again. It started but was not running right. Took the upper plenum off again. This time I laid out the fuel injector on a towel hook up the electrics and with a remote start button, cycled the engine and checked each injector. Some did not have a good spray so I replaced the whole injector set. The truck ran better. But soon started to get different trouble codes. When the o2 sensors showed up I installed 4 new Bosch wide band O2 sensors. Several other engine sensors where replaced. It ran okay but never the way it should. There was always a slite vibration and a sense that the engine was choking. after three years of use 11000 miles started to get misfire codes and the truck was running rough. This prompted me to do and ignition upgrade. Summit racing billet distributor, new high voltage coil, 8mm wires , and new crank sensor. I already had Bosch double platinum plugs, and they all checked okay. In came the whole Cam/Crank relearn thing. After straitening out the timing I took the truck to Chevy to see if they could reflash the computer. While there the tech thought the cat might be blocked. So I put on a new stainless steel replacement Magnaflow set of catalytic converters, and while I was at it I added a Magnaflow stainless steel cat back exhaust. Still have the underlying vibration, and the problem is different. At 1500-2100 is a miss or stumble. I believe that the truck is running rich. if you accelerate to 2500-3000 rpm it runs a little better but the vibration is still there. The 1st question is this In the later Firebird's and Camaro's you had to buy a flywheel-clutch-pressure plate set that was balanced together, was it the same for the trucks? Has anyone made any of these upgrades had smooth operation issues. Compression is between 175 and 185 psi per cylinder. Because # 8 was the lowest at 175. I pulled the heads to check. there seemed to be a heavy build up of carbon for only having 11000 miles. after replacing the head gaskets, and seals. made another compression test and that cylinder was still reading 175. I did replace the plugs with AC Delco, but it made no difference.

2 Answers


I didn't have a vibration on a Chevy but did on a Mustang 2 that I put in a late model roller 302 engine in, the machine shop just could' not get the balance right on the flywheel for some reason, I finally gave up on them and purchased a fluid vibration damper and bingo no more vibration. Might be worth a try, as it looks like you have spent a ton of cash trying to make this special. Have you thought about an ECM reprogrammer, with some of the engine mods an ECM with factory settings might be hurting you rather than helping. You also might try your local speed or hot rod shops in your area, new tech is coming out all the time, they maybe able to suggest some things for you. HTH

1 of 1 people found this helpful.


Your Answer

Add photo

Related Questions

  • No low end power 31 answers

    I have a '97 k1500 with a 350 and 4l60e automatic. Assuming all things are OK with the truck, would a bad fuel pressure regulator cause it to have no power at low rpm's? It always bogs under acceler...

    1997 Chevrolet C/K 1500


    Maintenance & Repair

  • 1998 Chevy Silverado has a drastic drop in mileage that my mechanic and I can't find the reason for 12 answers

    My '98 Chevy Silverado suddenly dropped 4 to 5 mpg so I had a full tune up with new plugs and wires, changed injector syst., changed O2 sensors, had purge valve cleaned in throttle body, changed fuel ...

    1998 Chevrolet C/K 1500 Cheyenne Standard Cab SB


    Maintenance & Repair

  • My '93 suburban misfires 1 answer

    All plugs are firing and the motor is timed correctly. Some plugs are wer tho... The truck has lack of power and backfires out the intake when revving. Compression is between 175 and 200 for all 8...

    1993 Chevrolet C/K 1500


    Maintenance & Repair

  • No power 1 answer

    My truck lost all power the windows don't work in can crank over the motor with a switch that is hooked up to my starter do to safety neutral switch is bad no power to nothing

    1991 Chevrolet C/K 1500 Silverado Extended Cab Stepside SB 4WD


    Maintenance & Repair

  • more power 2 answers

    hey so i have 1991 short box with a 4.3 fourwheel drive 5 speed the motor is completly stock right now do you have any ideas for fairly cheap engine mods ?

    1991 Chevrolet C/K 1500


    Car Customization

Search Chevrolet C/K 1500 Questions

Chevrolet C/K 1500 Experts

#1 Andrew Olsen
Andrew Olsen
Reputation 3,340
#2 John Saffrahn
John Saffrahn
Reputation 2,500
#3 Rowefast
Reputation 2,050
View All

Related Models For Sale

Used Chevrolet Silverado 1500
1,717 Great Deals out of 175,749 listings starting at $1,250
Used GMC Sierra 1500
822 Great Deals out of 68,199 listings starting at $2,484
Used Ford F-150
2,194 Great Deals out of 206,316 listings starting at $1,499
Used Chevrolet C/K 2500
214 listings starting at $2,250
Used Dodge Ram 1500
455 Great Deals out of 11,152 listings starting at $700
Used Chevrolet Silverado 1500HD
18 Great Deals out of 258 listings starting at $3,985
Used Chevrolet Silverado 2500HD
306 Great Deals out of 27,742 listings starting at $1,250
Used Chevrolet Tahoe
550 Great Deals out of 29,234 listings starting at $1,699
Used Chevrolet C/K 3500
237 listings starting at $4,995
Used Chevrolet Camaro
225 Great Deals out of 30,943 listings starting at $1,217
Used Toyota Tacoma
541 Great Deals out of 40,814 listings starting at $2,495
Used Chevrolet S-10
10 Great Deals out of 1,345 listings starting at $1,395
Used Chevrolet Colorado
217 Great Deals out of 24,313 listings starting at $2,495
Used Chevrolet Silverado Classic 1500
82 Great Deals out of 1,056 listings starting at $3,777

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use.