Bumpin' Yota

Now that the temps have dropped off down here, I notice that on start up the engine stumbles for about 2 seconds or so then recovers on it's own and begins the high idle warm up...

During the stumbling time of about 1-1.5 seconds or so the rpm is about 400. I have never had to give it gas, as after about 1.5 seconds or so it catches itself....

It NEVER did this in the past...could this be my Cold Start injector not operating properly?

3vze with automatic and 256,000 miles...

jimbo74

its old, i jsut say let it be... my truck takes a lot longer to catch itself when its cold out... most of the time, if i dotn give it gas, it will run for a sec, then stumble and die...

Bumpin' Yota

I'm too anal retentive not to do anything about it....lol This truck is my baby. lol

I'm going to pull codes tomorrow, but I'm betting I have none. Then perhaps a compression test too and or pull the cold start injector to see it's spray pattern...

jimbo74

my truck does it, but i attribute it to being a carb, with a mechanical fuel pump.. there really isnt any priming going on once the fuel drains, its takes a while to get the suction back up

Bumpin' Yota

ttt - havent done those things yet.....

Bumpin' Yota

ok pulled codes...

42 - for the vehicle speed sensor....if im correct isnt that near the back end of the tranny just forward of the torque converter?

However that would not induce a stumble at start up....grrrr

Bigblock

there will be no code because the comp is in open loop,running on the prom chip. after warmup of course the problem is gone ,after warmup the comp goes into closed loop, which is the only time it will recognise a problem and produce a code.you,more than likely, have a cold start timer trying to sh t on you.mine does this too so when i fix it i'll tell you what exactly is wrong.could also be a froze fuel cut relay.