99 Bravada many problems

I have more then one problem going on I'm thinking. Right now I am just wanting to get it starting again. It starts some days and others it just refuses. When I am driving it cold the oil pressure is a hair above 3/4's on the gauge. It also feels like it misses at certain speeds. (45mph and 65-70) The rpms are also around 2,700 at 70mph. Oil pressure drops back down to normal,rpms drop down and the misses get to be less once the car is driven about 150 miles. Once its heated up at idle at lights the oil pressure will drop below 1/4 mark on the gauge and the car will sputter unless i put it in neutral. When I'm trying to crank the car when it won't start it seems to be cranking faster then it should be. Also when that happens theres a hum that I can hear that doesn't go away unless I turn the key all the way back and then turn it forward again. I am assuming its the fuel pump that is making the noise but I can't hear it outside of the car and inside I can't really figure out where its coming from.
In the past few months I have replaced: fuel filter,spark plugs,wires, distributor cap and rotor, air filter, oil and filter.

My first thought was compression issues but I am trying to figure out a fix that maybe possible or any info before I take it in. I refuse to touch the plugs to check compression because of that horrible plug pinned in behind the steering coloum. If thats the problem I'll let the shop do it.

My second thought was something to do with the fuel system but I'm not sure because of most the time it starts then other days its just dead.

Any help would be greatly appreciated!

Welcome Aboard!

The three things needed to make an engine run should be checked - Fuel mixture, ignition, and compression.

It's unlikely that the compression would vary as you describe. Once there is enough wear or damage to lose compression, it rarely comes back by itself.

The ignition can be checked directly at the spark plugs with a spark tester or spare plug. Even a screwdriver held near a good ground will reveal the presence of spark - If you are brave enough to hold the screwdriver.

Testing fuel pressure would be a good idea. That system requires a minimum of 61 PSIG to reliably start the engine. I've seen some that would start as low as 58, and others that would never start at 60.

Thanks and thanks for responding also :smile:

I checked for spark by putting a spare on and it is firing. Would I need to check all of them or is one enough?

I don't have a fuel pressure gauge. Do you know a store I could get one and does it have to be a certain type? I checked autozone online but the website said they didn't have one for my car. I did push down on the tab where you hook one up at and gas came out so at least I know it is getting some gas.

Is it a nice blue spark?

Weird about the fuel pressure guage. I got mine at Auto Zone. Maybe call them?

Is it a nice blue spark?

Weird about the fuel pressure guage. I got mine at Auto Zone. Maybe call them?

No...it was actually a dark orange. I'm guessing its supposed to be blue? If its not throwing a hot enough spark then what does that mean?

Maybe it was just not available online.

I just went through this with mine. You need a blue spark. When you did the cap and rotor, did you replace the wire going from the coil to the dist?

Maybe pop the cap and check for corrosion on the little metal nubs in there, or on the rotor... You could also check and clean the two wire harnesses that are by the coil. One goes to the ignition control module and the other to the coil.

Okay my buddy and I were out messing with it and when I did the spark test earlier I forgot to ground the thing. Now that I did that there was a whitish blue spark. He thinks that it is not sparking right though and is thinking maybe the distributor needs to be replaced. It smells like it is getting plenty of gas and when I took the spark plug out you could smell it pretty good. Tomorrow I will take the cap off and clean everything and blow dry it to make sure everything in there is dry. I'll also do the check on the wires to it.
I heard the fuel pump come on and turn off after a few seconds when he started it so that's a plus. He also heard the strange hum inside the car with the key turned forward but he could not figure out where it was coming from or what it would be.

Fuel pressure test kits are available at most auto parts stores and Harbor Freight sometimes has them on sale. Here's where to connect it:

http://i131.photobucket.com/albums/p288/Clunk_/Image026.jpg

It'll also check the lift pump fuel pressure on a '98.5-02 Dodge w/Cummins diesel.

Thanks Chris.
Tonight I pulled the distributor cap and rotor off. I cleaned the contact points and blow dried them. It started up and I took it for a test drive and everything actually seems to be fixed. Oil pressure was acting normal and no chugging at any speeds. The rotor tab was a little green so I'm guessing maybe moisture got in there. Hopefully it starts tomorrow morning and keeps going. I'll keep everyone updated and thanks for all the help!

Good work.
Looks like the distributor cap messed up kinda quick huh?

Well since I have done that it rained about 3 days after and it would not start again. I took it out and did the same thing and it started back up and I haven't had the starting problem since. I did use to rough of sandpaper on the rotor tab though and its been chugging. My guess is because I left grooves in the tab. Once I get the money for it I"m putting a new cap and rotor on and then putting silicone on the cap. If that does not fix it I'm guessing the plugs were the cause of letting moisture in.
Wish they had a warranty on this stuff.

Good work,
You might try looking at the rubber seal between the cowl & hood and maybe spray some Armorall and wipe it real good.