Lagging when I accelerate

Asked by PrettyLadyinAk Oct 25, 2017 at 08:10 PM about the 2001 Chevrolet Tahoe LT 4WD

Question type: Maintenance & Repair

Replaced all coil packs full tune up And all four 02 sensors
Still lagging when I accelerate , any ideas ? Only shows up
on diagnostic as a random multiple misfire , yet they're all
firing .

2 Answers

7,355

Your mechanical timing could be out, could have a bad fuel injector(s) or a valve issue are the things that come to mind. The first things I'd do is make sure you do not have a vacuum leak (brake cleaner/starting fluid can help with that) and do a compression test, if it's a mechanical problem you can throw all the sensors/modules at it you want but it will never solve the problem. If you find that one cylinder is really low compared to the rest the next step would be to make sure you set THAT cylinder to TDC so both valves are fully closed, pull the spark plug and use a air compressor to blow air into that cylinder. You can use a piece of hose that will snugly fit into th spark plug hole and use an air wand connected to the hose to get air in but be careful not to giver full blast! If you can hear air through the muffler you have have bad exhaust valve, through the throttle body is a bad intake valve and through the oil fill spot or through the oil dipstick would be a bad piston. If you have low compression on 2 adjacent cylinders then you most likely have a bad head gasket. Beyond that I would suspect the cam postion sensor or possibly ignition control module. I know that's a lot to take in, it's not easy trying to diagnose without the car. I hope this helps

7,355

Mass Air Flow sensors are common issues on your vehicle also. Just for good measure though replace your fuel filter (if you didn't do it recently) before proceeding with anything else

Your Answer:

CarGurus Experts

  • #1
    John Carson
    Reputation
    3,570
  • #2
    Rowefast
    Reputation
    2,290
  • #3
    Gene Arnett
    Reputation
    2,150
View All

Find great deals from top-rated dealers

Search

Related Models For Sale

Used GMC Yukon
15 Great Deals out of 966 listings starting at $5,890
Used Chevrolet Suburban
14 Great Deals out of 536 listings starting at $10,950
Used Cadillac Escalade
13 Great Deals out of 510 listings starting at $5,931
Used Chevrolet Silverado 1500
212 Great Deals out of 8,092 listings starting at $6,995
Used Ford Expedition
20 Great Deals out of 654 listings starting at $7,894
Used Ford F-150
318 Great Deals out of 13,660 listings starting at $3,800
Used Toyota 4Runner
26 Great Deals out of 540 listings starting at $7,700
Used Dodge Durango
51 Great Deals out of 1,870 listings starting at $6,987
Used Ford Explorer
65 Great Deals out of 2,071 listings starting at $3,333
Used GMC Yukon XL
10 Great Deals out of 722 listings starting at $11,500
Used GMC Sierra 1500
140 Great Deals out of 8,304 listings starting at $5,500
Used Toyota Sequoia
3 Great Deals out of 52 listings starting at $19,990
Used Jeep Grand Cherokee
124 Great Deals out of 3,505 listings starting at $4,950

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. Content will be removed if CarGurus becomes aware that it violates our policies.