ok I will swap injectors/plug wires and see how that goes. one thing I just noticed is that since the temp here in tx dropped to 35 degrees tonight my truck is running way worse than it was before. my CEL started flashing and the engine is stumbling badly, almost as if it were starving for fuel and I could here backfiring in the engine bay. I am sure cold weather makes it worse. Does that help narrow things down any?

 

what codes did the PCM give when it was flashing? did it continue when it warmed up?

 

yes it continued so I stopped driving it last night. this morning I took it to have the codes pulled again and I now have cylinder 5, 6 and 8 misfire along with P0300 random misfire code. The truck is 100% worse than before. Stumbling so bad it shakes the entire truck if I apply throttle without allowing the trans. to down shif to a lower gear. I take it this is because I now have 3 cylinders misfiring instead of 2.

the cel is no longer flashing since the weather has warmed up, but running horrible. thanks.

 

man ... thast rough dude... id defentatly have to say you have some really bad cracks in the heads... or a really messed up feul system....goodluck dude

 

check the fuel pressure at idle and then under load... drive it w/the gauge hooked up and see if ti stays @ 49.5 psi. you may have a bad fuel pump.

oh and one other thing to try... if cold weather makes it worse and it's a random mis-fire... take a blow dryer to the coil and heat it up some, if it runs good, then your coil is bad... then check the fuel pump.

 

ok I put another coil on and bought another set of wires...same prob. where can I tap a fuel pressure gauge in? I don't see a fitting on either fuel rail. I myself am leaning towards it being the fuel pump or injectors failing. Thanks.

 

there should be a schrader valve on the fuel rail (some years dont have one for some reason) where you can check the fuel pressure. I doubt it's fuel injectors... all of them wouldnt go bad at the same time... look towards the fuel pump.

 

ok thanks steve and the others that helped me out here. There isn't a shrader valve on mine so I am going to do the fuel pump assembly and hope for the best. I bought the truck new and it now has 138k miles on it. The pump has never been changed so I figure it can't hurt to do so.

Am I correct that the fuel pump assembly in the tank consists of pump, regulator, relay and filter?

The price at autozone for the assembly is $310.00. Any suggestions on what I should purchase as far as upgrade or aftermarket? Or go to the dealer?


The truck got progressively worse and now it never runs smooth even at highway speeds. If I am at 60 mph and give it throttle the engine shakes and stumbles badly causing the cel to flash 9 or so times in a row sometimes as many as 18 flashes. I am also getting more cylinders that are misfiring It never did this before, but I suppose fixing some of the problems worsened others.

 

Ok I didn't end up going out of state and had some time to work on my truck. I took it to the dealer on thursday and had the fuel pressure checked along with other diagnostics. They were unable to determine what was going on so I decided to cut my losses and pay the 2 hours ($154.00) labor and leave. It was such a waste of time and money going there and will not happen again. Anyway, I decided to have another look inside the throttle body...oil was present in the manifold AGAIN. I take it out again and the plenum pan gasket was loose and taking in all sorts of oil around the entire gasket. I take it this is the reason it started running worse than it ever had in the past.

I did not have new intake bolts and when I set my wrench to begin to torquing to 48 in. pounds the bolts just stretched. One of them gave and twisted off completely, I don't know how I could possibly get them to 84 in. pounds without stripping the manifold or breaking the bolts.

Will new bolts have a better response to the torque specs? The dealer was closed and the locals parts stored didn't sell grade 8 bolts. I just need someones opinion on this before I go torquing away...the last thing I want is to strip the manifold. Thanks.

 

Those particular bolts for the manifold plenum cover are only good for 1 torqueing.They have a special designation or name that I can't recall right now but yes, a new set of bolts and you will be able to torque them to specs.Use a good sealer along with the gasket,also,if you have any isopropyl alcohol , use it to clean the mating surfaces,isopropyl is about the only thing that will not leave a residue and silcone/rubber sealer sticks much better.You can get it at about any drug store or wal-mart.[gasoline,brakeclean,carb cleaners all leave a residue even tho you can't see it]

By the way, the bolts are a "torque to yield" type and I found the following information on them even tho this article talks about cyl head bolts it applies to all TTY bolts:

What is Torque-To-Yield?
All bolts stretch when tightened. When stretched, a bolt tries to return to its original length, much like a spring. It is this elastic quality that provides the clamping force necessary to seal a gasket properly. When a bolt is stretched to the point it can no longer return to its original length, it is permanently distorted and has reached its yield point. After a bolt has yielded, it can no longer provide its full clamping force.

Why do Manufacturers use Torque-To-Yield?
Engine designers prefer the use of TTY bolts for several reasons; TTY bolts:

Provide more uniform and accurate clamping force on the head gasket, resulting in improved engine performance and reliability.
Deliver 100% of their strength, by comparison conventional bolts only use about 75% of their strength.
Prevent over-tightening of the head gasket.
Generally eliminate the need to re-torque after a break-in period.
Eliminate the inconsistent clamping forces created by the friction-tightening method.

Can Torque-To-Yield bolts be re-used?
Most engine manufacturers require new TTY bolts be installed whenever head bolts are removed. A few do provide guidelines on re-use of the original bolts. The problem with re-use is there is no accurate visual method of determining their condition, and most repair facilities do not have the capability of accurately testing them. Cylinder head bolts provide the clamping force necessary for the head gasket to properly seal and function. Uneven or improper clamping force will cause a head gasket to fail prematurely.
It is recommended to replace TTY bolts whenever they are removed.