99 Sierra hesitates during acceleration after cruising at speed for a while
I have a 99 sierra. When I cruise at backcountry speeds around 45-55, and then
accelerate a little for a speed limit increase, I notice the truck sputter and hesitate, a few
times it even popped a little. What could it be? It seems to clear up after I push harder on
the accelerator, but it happens several times in a trip.
It sounds like an ignition misfire. Have you tuned it up lately (spark plugs, wires, cap & rotor)?
I'm sure it could use a tune up, I just bought it a few months ago. Is it odd that it only happens occassionally though? Its not every time that I leave from a stop sign or something, it's after I've been going a while and then change speed
I've seen this happen when the engine is under partial load. When you are in 4th gear with the torque converter clutch engaged, and lightly accelerate. Once you put you foot into the throttle, the TCC shuts off, the load eases-up on the engine, and it stops missing.
Start with general maintenance (tune-up). A new fuel filter and PCV valve would be good too. Check the air filter and replace if needed.
Since you just purchased it,.... if you supply me with the following info., I can make a list of some problem areas to check. Miles on vehicle, engine size, 4 or 2 wheel drive, auto or stick shift (I assumed auto).
its a 4.8 4wd auto with 142k.
Had the same issue with my 1999 GMC Sierra Z71 truck, after spending oodles of $ on about everyting from a tune up to the fuel system....I found out it was the Mass Air Flow Sensor. If you notice the truck kicks out a cloud of smoke when you jam the pedal down, check your Fuel Pressure regulator. I also had an issue when that was bad. I don't have a picture, but if you can locate the fuel pressure regulator under the hood, while the vehicel is OFF, unhook the lower tube and if it drips, while OFF, then that is an issue. Change it ($35,00 I think)...the Mass Air Flow Sesor was like $43, installed. Good Luck.
In general if an engine just cuts out (instantaneously) its usually related to ignition or engine management, if it's more gradual (loss of power, sputtering etc., usually fuel delivery problem) If you have a check engine light, see if you can get a code, to narrow down your search.
I thinks its the mass air flow sensor, my 99 Sonoma is hard on them. I will clean mine tomorrow and see how it runs.
I have a 2000 gmc sierra 4.3 and ive changed the cadalytic converter and thats why my engine light was on. Well i was driving back home from work and when i hit 3000 rpms to speed up on the service road my truck sputters like it was out of gas then losed all power but then randomly came back on and never did it again while driving home any ideas what could cause that?
I have a 2000 GMC 5.3 vortec. I had similar hesitation on acceleration. Code came up when having transmission work and it was mass airflow sensor. I put an after market cold air intake on 6 months ago. So, not sure if that added to its demise 210k miles on it though. So, not too bad. Anyway, easy to do yourself. Delphi or AC Delco about $100.00 and change with 15-20 min labor.
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