Massive hesitation, SES light flashing :(

[nimrod.sixty9]

Will wait for pics and what about the codes I asked about. Can eliminate a head gasket issue for sure.

Dont know anything about the codes. Same ones shown when I got the truck (scanned from AZ); replaced the sensors, didn't show up until I used ScanXL.

Also, compression check was dry, with plugs 1,3,5, and 7 removed.

 

[Tacky]

You do not give a lot to work with. Have you used a spark tester on #3 plug wire? It sounds like you are loosing spark under load, may be a bad plug wire and/or distributor cap

 

[SunlitComet]

NGK's? get the crap out of there and use delco 41-993 or autolite xp605's. And do not ever gap or attempt to re-gap non copper core type plugs. Do a resistance check of the spark wire and look inside the cap for burn marks or arcing that would indicate the spark is jumping around. Delphi or Delco or Msd parts for that stuff if needed. From the looks of it 3 looks like it is lacking a spark but is getting fuel and 1 is getting to much fuel. 5 and 7 look normal.

 

[nimrod.sixty9]

Had some ACdelco laying around I never installed, put them in and now have a world of difference. However, Im still not satisfied... Seemed it may had a small miss at highway. So small infact, I could not tell if it was a mis or the highway itself (Florida roads are horrible). Still, ran a million times better, idles perfectly, etc... Had a bit of a stumble the first time I got on it when shifting to secnd. Almost seemed indecicive. Only happened once.

Think I may put the old cap and rotor back on. What you think?

How about that low psi in cyl 3?

Also did FP test and leak down test. hit 55psi and stayed. Dropped about 3 PSI after about 8 minutes.

 

[SunlitComet]

while it is low and may stand out a bit it is not low enough (compared to the other 3) to consider a ring job. I will tell you this, when i got my suv it had misfires in 2 cylinders because the old injectors were dumping to much fuel. Caused backfiring in the intake as well. That extra fuel was washing out the cylinders and as a result had lower compression then the others. All the issues went away when the spider was replaced as well as new ignition components. If unable to determine make and age of cap and rotor put in new delphi, delco or msd ones in. Fuel pump is old but still hopping along just fine.

 

[nimrod.sixty9]

while it is low and may stand out a bit it is not low enough (compared to the other 3) to consider a ring job. I will tell you this, when i got my suv it had misfires in 2 cylinders because the old injectors were dumping to much fuel. Caused backfiring in the intake as well. That extra fuel was washing out the cylinders and as a result had lower compression then the others. All the issues went away when the spider was replaced as well as new ignition components. If unable to determine make and age of cap and rotor put in new delphi, delco or msd ones in. Fuel pump is old but still hopping along just fine.

I believe the cap is delco and about 6 months old. I believe Ive done the leak down test properly, but Im still not convinced. Maybe fuel and spark is good, but intake gasket not so much?

Also, I dont know if I mentioned this before, but when I pulled the wire off of the coil, I pretty much had no rsistance. Im not sure if it was all the way down. But if this was the case, would I not have missfires all over the place rather than just cyl three?

 

[SunlitComet]

Yes they would be multiple however take in consideration how the cap is wired and the possibility for some easy shorts and ones that are less likely. Strange things com of that.

---------- Post added at 11:35 AM ---------- Previous post was at 11:34 AM ----------

Concentrate on full diagnostics of everything related to cyl 3 be it leak down, ignition and stuff.

 

[nimrod.sixty9]

It's back. Except this time its only P300. Suddenly runs like poo, out of nowhere.

Why would it be fine for two months after replacing a plug and suddenly bad again?

Still considering putting on the old cap.

 

[gpracer1]

"I notice water/coolant on the intake around the thermostat housing and rear of the compressor. Look in rad and I cant see anything. GF said she never saw the temp go up... FML"


That part would bother me.

 

[nimrod.sixty9]

"I notice water/coolant on the intake around the thermostat housing and rear of the compressor. Look in rad and I cant see anything. GF said she never saw the temp go up... FML"


That part would bother me.

Already fixed, was thermostat gasket. Just looked and antifreeze is there again. **** this truck...