Misfire issue

[beardeddummy]

Ok well it did something funny today it felt it lost power for a split second twice. I almost thought it was he transmission slipping but no change in rpms. I need help this is bothering me

 

[Fuzzy]

Okay Few more questions;

Have you done a compression test on that cylinder? If not you need to before checking anything else, if you have compression loss then there's no point in chasing parts.

Have you checked the spark plug that is in the cylinder that is misfiring to see if it's firing, fouling, covered in gas? Compare it to one next to it, or even better one from the other bank.

Is your truck the Factory Spider or the Upgraded MPFI Spider?

Does your truck ever smoke or take a while to crank?

Have you checked fuel pressure?

 

[Supercharged111]

If it was compression, it'd be a problem all the time.

 

[beardeddummy]

Plugs look good will do compression test soon. upgraded spider. my truck always forest up instantly. I'm spoiled by it. all I do in my wife's truck is bump the starter. it has seemed to drag a little once or twice I wrote it off thinking I left the dome light or something on I'm bad about that.

 

[beardeddummy]

Update my maf is reading 2.53 g/s with the engine off. this would be the same as a 2.5l motor idling. so it's calling for that much more fuel constantly

 

[Mrich0908]

Doesnt sound right to me. unplug the maf . It will go into speed density mode. If it fixes your problem get a new one.
Unplug your egt sensor also. You could get a spark plug test light from harbor freight there like 10$ see if all cylinders are firing off properly.
Both ECT sensors are reading the temp properly if not if will make your motor run really ruff.
Broken ceramic on a plug? Fouled plugs? Melted wire? Rotor? Distributor gear ? Cam CPM is set to exactly 0? Map sensors ok?

 

[beardeddummy]

Map sensor is fairly new. cam retard reads -2. unplugged maf and it didn't misfire as much. wires and plugs are good. just warrantied cap and rotor again. also about to install a new o2 sensor on bank 2 every time I do something it seems to get a little better but has always done that.

Now cam retard is 0

 

[Red Bowtie]

Hi,

I was having a very similar issue with it missing at idle and stumbling coming off idle etc. but no codes. I finally tracked it down to the IAC. After I replaced it that took of the missing and the stumbling.

Hope this helps.

Eric

Old school here, we spell everything out What is IAC? sounds like it might fix my '97 Silverado if I know what to look for.
Thx

 

[beardeddummy]

Idle air control valve. what's your 97 doing?

 

[Red Bowtie]

Idle air control valve. what's your 97 doing?

I call it a hick-up, the

Idle air control valve. what's your 97 doing?

OK, now i know what your talking about I ask a mechanic friend if it could be that or any other control modules and he said no. Sounds and feels like the tranny.
beardeddummy you know how chevy always had a A/T overdrive that cut in at 35 ? well mine duz that but if there is any kind of hill or step up in the tranny to get another gear the truck wants to HICK-UP. feels like it jumps and bucks till i let off of gas then its ok.
it duz not do it all the time. mainly when the truck has warmed up and rolling down the highway. If i clean the carbon out the pipes it shifts fine. hot or cold. but just cruzing the highway and a little hill or need for speed , there it goes. Hick-up.
this a V8 that runs strong rebuilt about 50M miles ago along with the tranny but still dont have an answer. I have only had the truck 3 months so im still learning bumps creeks and noises, but i know that is not right. wish i could explain more but its hard to say.
Thx man!