Chugging / Bucking Cavalier

[UrbanSherpa]

1995 Cav 2.2 5spd 180,000km


Intermittent 'chugging'. Usually the car is fine for about 2-5 minutes
after a cold start, then starts chugging for the rest of the drive.
Almost feels like someone is depressing the accelerator pedal and
releasing quickly when accelerating. When maintaining speed it still
chugs and feels like it is missing. When coasting down it smooths out.
Also sounds rough at idle.
It is not a clutch problem as clutch seems to work fine, no slipping
(under hard acceleration before chugging starts).


I've changed the plugs, replaced the fuel filter, and even tried
unplugging the EGR vacuum hose (someone suggested this tactic once)
Been thru several tanks of gas, and injector cleaner.

My next guess is to replace the O2 sensor....Can anyone tell me where it is???, and how to?


I'd certainly appreciate ANY help you could give me as it is a pain in
the ass driving down the road like this (and probably looks funny too!)
Feels like a beginner learning to drive a stick.


karl takethispartout [email protected]

[zeptech]

Originally Posted by UrbanSherpa

1995 Cav 2.2 5spd 180,000km


Intermittent 'chugging'. Usually the car is fine for about 2-5 minutes
after a cold start, then starts chugging for the rest of the drive.
Almost feels like someone is depressing the accelerator pedal and
releasing quickly when accelerating. When maintaining speed it still
chugs and feels like it is missing. When coasting down it smooths out.
Also sounds rough at idle.
It is not a clutch problem as clutch seems to work fine, no slipping
(under hard acceleration before chugging starts).


I've changed the plugs, replaced the fuel filter, and even tried
unplugging the EGR vacuum hose (someone suggested this tactic once)
Been thru several tanks of gas, and injector cleaner.

My next guess is to replace the O2 sensor....Can anyone tell me where it is???, and how to?

I'd certainly appreciate ANY help you could give me as it is a pain in
the ass driving down the road like this (and probably looks funny too!)
Feels like a beginner learning to drive a stick.


karl takethispartout [email protected]

try plug wires gently spay with water in the dark if bad will ark out u will see

[CathieB]

Hi there! I am new to this forum and basically car illiterate. I was curious if your issue has been resolved, because my problem is very similar to your description - the 'new driver' bucking is a great description. My 95 Cavalier (stick), hesitate/sputters on acceleration only on occasion and for no determinable reason. It lasts about 30-45 seconds, comes out of it and then drives perfectly. Sometimes it happens daily - sometimes it goes for days without happening. Sometimes the check engine light comes on - sometimes it doesn't. I have had it in the shop 8 times for this same issue (I know... I know) and they cannot seem to find the problem. They have done a full tune-up, replaced the EGR valve, solenoid, valve gasket cover and a PROM. I am at my wits end and so are the mechanics. They are not charging me any more money, but I am really tired of this issue and tired of having my car in the shop. The car only has 76,000 miles on it and has been great - in 10 years, I have only had to replace the battery, tires and a fuel pump (2 years ago). I do a lot of city driving and change the oil religiously (ok, have it changed). Help me!!! Thanks - Cathie

[jasnic44]

I have this exact problem as well with my 98 cav Z24 and I am glad the post above noted they had changed the fuel pump because I was going to do that which would be very difficult so now I can count that out! So hopefully someone will reply and help all of us!! Please Help!!!!!!

[CathieB]

Well - I have been doing some research and this issue on the Cavalier appears to be pretty popular considering my posting has 219 views and others with a similar title have a huge number of views/hits, too. Unfortunately, no one has posted a resolution to this chugging/bucking Cavalier issue on this site or any other site I have posted the question to. I finally contacted Chevrolet directly and was told, well, nothing other than to take it to one of their dealers (oh, boy ... $$$$). I talked with my mechanic, and we will take it to a local Chevy dealer (just for grins) to see if their diagnostics come up with something new & different. My mechanic's codes came up '27 Code QOM Fault & 32 Code EGR Valve & Solenoid' which they repaired and my Cavalier continues to do the 'funky locomotion' whenever it feels like it. If the dealership can't figure it out, I plan to go straight to the big brass at Chevy and let them know they have a potential safety issue on their hands with the 95ish Cavaliers. Maybe if all of you who are viewing this with a similar issue could respond, it could provide us some leverage with Chevrolet. I can't help but now look at this as a safety and possible recall issue. Sorry - I'm normally not a 'rouser' and this is totally out of character for me, but I'm ticked that so many of us cannot get this fixed on what is really a pretty darn good car! And I'm worried about some Hummer may come roaring in to one of us when our cars decide to do the "funky locomotion" dance! Thanks for listening - Cathie

[jgutierrez]

I also have this problem with my 99 Cav with Standard Tranny. I replaced the fuel filter, wires, plugs, MAP Sensor, TPS, Coils, injectors and am about ready to trade it. Took it to a Chevy dealer and scanned it with the hi dollar techno scanner. All they could tell from all of the screens was that it had a five count miss. Hi dollar scanner and mechanic could not tell me the problem. At least they didn't charge me for it. Mechanic told me to let him know what it was when I found the problem.The car bucks all the time. Ran great to about 140000 miles then started doing the bucking bronc. Anyone found a cure???

[CathieB]

I'm so sorry you are experiencing this same problem. Neither my mechanic, Firestone, or 2 dealerships were able to determine what was causing the 'chugging / bucking' of my 1995 Cavalier. They replaced the fuel pump (which was only 2 years old) and everything else I described above and still no luck - the car was practically re-built and it still chugged and bucked randomly. I truly believe this is a defect of some sort with the Cavaliers and should be a recall. Personally, I no longer felt safe in the vehicle and since no one could determine what was wrong with it, I am now the proud owner of a 2006 Scion tC! Be careful and good luck. Cathie

[KustmAce]

My car did the exact same thing about 2 months after I bough it. A new clutch fixed it.

[spaceman88]

i can only say two things... make sure your motor mounts arent shot, because your engine will buck really hard if they are... there should be four, two on the sides, one in the front, and one in the back..... and also make sure all of your cylinders are firing correctly, including spark plugs and distributor cap.... my friend had a similar problem and found water in two of his cylinder which stopped them from firing, and made his car shake ridiculously.... check those out, hope this helps.... i didnt read the answers from other people so i dont know if they said the same thing....

[mcrocks]

I have a 90' and a 93' cavalier that had a very similar problem. Nobody could figure out what was wrong with it. Took it to 3 different Cheverolet dealers. Being frustrated with the whole thing my father sent me to a mechanic who did work at his house during his spare time. This mechanic worked for one of the dealers previously gone to. To make this story short he figured out it was a solenoid in the transmission that was going out. Gave us the option of a new transmission or disconnectiong the connection to the soleniod. He told us we would get a little less gas mileage, but it would not hurt anything. Could not tell the difference in the gas mileage and it lasted for years after. Good luck

[Lonnie.Strunk]

wiggle wire harness while car is running that comes from behind engine going to injectors will car is running....mine would just shut off....this happened at 70 mph or 30 mps intermittenly....found by accident....plug in this harness behind engine was loose....which was cutting fuel off sometimes.....when this happened...would alway start immediately....

[NJH_Habitatpro]

Well i had this problem with a past car it was the vacuum hoses. So check them you can either do what i did and just bought some little clamps you tighting on there like on a air intake kit. Tighten them around all the vacuum hoses and that fixed it. or you can get warm water with a little soap in it and start your car spray the hoses lightly car bogs down you have a leak.

[Lord_of_Mice]

I too have this problem, on '96 2.2L. Changed all the usual, iat,iac,tps,egr,map,plugs,fuel pump, fuel pres. reg., and filter,and O2 sensor.
checked all the grounds, owner before me changed the injectors and the pcm. Compression check and fuel pressure are ok.
I am now down to guessing, has anyone changed the crankshaft position sensor and had any luck?
(shift points are not a problem(auto trans), so I assume the tcc valve and solenoid are ok)

[JGarretson]

My cavvy does not seem to do this as severe as the original poster's. BUT, it does seem to cut out intermittenly at a cruising speed. I can be doing 30 or 90 and it does the same thing. My guess is that an ignition coil is shot. I've changed the plugs, wires (were arching), and fuel filter. Its a 4 sp auto so it has nothing to do with a clutch problem.
The past couple of days on the highway it seems to be down shifting at cruising speed, but I think that has to do with the lack of power from the mis-firing cylinder. Also, I'm not getting any better than 25mpg at the moment, and this is supposed to be my "fuel efficient" car out of the 3 I own.

Other than this problem (and another CTS wire that is again broken, the car runs fine and has no CEL)

Any other suggestions?

[mikemartin123]

I have a 96 and a 97 Sunfire in the family. Both 2.2 auto. The 97 is OK, but the 96 has suffered from this bucking problem for about 3-4 months. Quite a high mileage car though. Dealer has not been able to solve. Over the period - new fuel pump (was intermittant, new fuel filter, new fuel pressure regulator, new ignition coils, new wires and plugs, new MAP, new PCV, Aire filter, throttle body and upper intake manifold cleaned/serviced, TPS and IAC checked OK. Vacume hoses/lines vacume checked for leaks. Has never set a DTC code. Chugs at any speed, but never under acceleration loads. Can also happen at idle causing a stall. Has occasionally actually stalled while crusing at steady state. Also can be fine for days, can happen ocassionally, or can act up for days in a row leaving you wondering if you will get to your destination.
As with most of you I'm sure - leaving me very frustrated, and wallet thin. Not many placed left to go. I will however be trying the wiring wiggle trick next - as has also been previously sugested by one poster.