Stumbling / buckling only during warmup

[cptnsolo77]

Having trouble with my 03 vibe. Stumbling / buckling only during warmup. After it warms up I cant tell theres anything wrong. Cleaned the MAF, IAT, throttle body and IAC valve. I have a PO442 and P0420 ( cat and evap ) and they have been on there for years. I was thinking it was a misfire but it doesn't do it after its warmed up. Shouldnt a misfire be present when hot and cold ? I was thinking trans but I did a drain and fill last year on the trans. The car has about 310K. My next step is to check the plugs because it does burn oil. Been replacing the plugs more often so they dont foul up. It burns about 1qt per 1000 miles. Any ideas ? Torque app doesnt show anything out of the ordinary except the codes. Thx !!!

 

[CharBaby]

I'm just shooting from the hip here but, you may have found you own problem!
Do you have a CEL?
The engine may be stumbling upon warm up(only) until it burns off all of the oil from the plugs that you mentioned you're often replacing.
Do you get any exhaust smoke upon startup? It seems as though you should be.

Your P0420 could be the Cat becoming contaminated by the burning oil/blow-by
The P0442 could be(my thinking) completely unrelated as it is an EVAP code.

 

[JimPghPA]

Remove the EGR valve and clean out both the gas in and gas out passage ways.

A thin braded steel wire like the ones used for hood and gas cap release, put into a hand dril works well. It gives you length to get all the way in, and the end bouncing around from turning knocks loose the carbon buildup.

Be sure you vacuum out all you break loose. If a piece gets sucked into the engine it can destroy a cylinder wall and piston.

The valve sometimes can be cleaned. If not, replace it.

And either way, use new gaskets.

 

[cptnsolo77]

I'm just shooting from the hip here but, you may have found you own problem!
Do you have a CEL?
The engine may be stumbling upon warm up(only) until it burns off all of the oil from the plugs that you mentioned you're often replacing.
Do you get any exhaust smoke upon startup? It seems as though you should be.

Your P0420 could be the Cat becoming contaminated by the burning oil/blow-by
The P0442 could be(my thinking) completely unrelated as it is an EVAP code.

I'm just shooting from the hip here but, you may have found you own problem!
Do you have a CEL?
The engine may be stumbling upon warm up(only) until it burns off all of the oil from the plugs that you mentioned you're often replacing.
Do you get any exhaust smoke upon startup? It seems as though you should be.

Your P0420 could be the Cat becoming contaminated by the burning oil/blow-by
The P0442 could be(my thinking) completely unrelated as it is an EVAP code.

Its been a while since I have checked for smoke on startup, but I will check now. Thx !

 

[cptnsolo77]

UPDATED : Looks like I found my problem. Pulled plugs and ALL 4 were wet with gas. One plug the porcelain was cracked at the base where the socket goes over too. Leaking injectors I guess ? How do all 4 injectors go bad ? I have been putting marvel mystery oil in the tank for the last couple of years on each fillup. I went according to the instructions. Maybe I have been putting too much and damaged all the injectors ? ****...this sucks. This would also explain my hard start after its been sitting for a while. I did do a quick test drive after I replaced the plugs and looks like my bucking / stumbling was a misfire. With the new plugs it drove fine during the warmup. Thoughts ???

 

[wlk]

UPDATED : Looks like I found my problem. Pulled plugs and ALL 4 were wet with gas. One plug the porcelain was cracked at the base where the socket goes over too. Leaking injectors I guess ? How do all 4 injectors go bad ? I have been putting marvel mystery oil in the tank for the last couple of years on each fillup. I went according to the instructions. Maybe I have been putting too much and damaged all the injectors ? ****...this sucks. This would also explain my hard start after its been sitting for a while. I did do a quick test drive after I replaced the plugs and looks like my bucking / stumbling was a misfire. With the new plugs it drove fine during the warmup. Thoughts ???

Run 2 cans of Berryman's B12 Chemtool or Gumout Multisystem Tune Up through it and see if it cleans the injectors. I'd use Berryman's as it is 1/2 the cost and is a very good.
Also could have been the cracked porcelain all along.

 

[cptnsolo77]

Run 2 cans of Berryman's B12 Chemtool or Gumout Multisystem Tune Up through it and see if it cleans the injectors. I'd use Berryman's as it is 1/2 the cost and is a very good.
Also could have been the cracked porcelain all along.

Appreciate the advice ! My next thought was to run some injector cleaner and see what happens. I was going to run a can of BG44K but it looks like berrymans is aimed at the fuel injectors specifically. I havent tried any berryman products so this will be a good time.

 

[ElectroMechanoMan]

Certainly could be all 4 injectors at that mileage. I thought about fuel pressure, but I would think it would throw a code.