shoggoth80

Hey all.
This has been a recurring issue in my Jeep recently. Typically happens about 55-65mph. Occasionally at slower speeds, though not often. Highly irritating.
It only happens under load. I can clutch it, and the engine will rev fine. I don't have a tach, so I have no idea what RPMs this happens at.

At first I thought it could be related to a number of sensors. Between replacing some, and testing others, this does not seem to be the issue.

I was paranoid about a possible head gasket leak, or a cracked head causing the problems. I occasionally have to add a little coolant, but few and far between, and it is possible that I am running a little hot, or it dribbles a little bit around the pump seal. Haven't been able to really verify this. If I open up my valve cover, my oil smells a little like exhaust. Is this indicative of a head problem?

I have also tested fuel pressure at the rail... in a 2.5L engine, it's supposed to be 31psi, and it tested at 30psi solid, even while revving. That 1psi could just be a slight error in gauge calibration, or my father might not have caught the dial right at the 1 marker... as they are small, and he is getting older (I was behind the gas pedal to rev it).

The problem is that it happens intermittently. It did it while driving to my friend's house today, and did it driving him back home... but the Jeep ran perfect for the 45mile trip back home. This particular gremlin has me scratching my head a bit.

I know that some of these issues can be caused by problems with the cylinder head, but they can also be caused by the fuel pump as well. Pretty sure mine is stock... it's never been out of the car since I have had it. I did replace the fuel filter not too long ago, as that was the first suspect in this case. Any thoughts, or possible insights?

I briefly thought that the timing chain, tensioner, or dampener might be worn, but it doesn't feel like a timing problem. The engine loses power, like it has no fuel going to it, backfires a bit, and then resumes. So I am thinking either fuel related, or perhaps after it is hot, there is a leak around the head gasket, pulling in air, or a little water or something. Just has me baffled. Any help would be good. I've been searching the threads, and google... and the fuel pump going intermittently, or a head issue are the only things that I can think of that cause these issues.

shoggoth80

No input or insight?

Slick761

Could be your.injectors....

shoggoth80

I have not ruled out the possibility of dirty injectors... though I have run injector cleaner through the gas several times. I do not know how well any of that stuff actually works. I have a replacement set of injectors... they are going in later this week. A set of 703s to boot. I will also be doing the head gasket on the same day. Then I can inspect the valve-train, and the condition of the head itself.

I am a little paranoid that it *could* be the pump, as that is a symptom that will not give a check engine light (along with my other suspects). It also bothers me because pretty much all I can find is Airtex brand pumps, at least in terms of full drop in units. I know Airtex does not have a reputation that is worth considering. I could order other brands through Napa or whatever Schucks turned into, but that would be a more involved affair (though not greatly so). Have yet to check with a dealer, though that might not be the worst option to look into, should the pump prove to be the culprit. It's tough when a number of components can cause one symptom.

Slick761

Ya injector cleaner works a little but not great. Once again I'm gonna get kicked, am I the only one with an airtex pump tears still working? I think its actually been a year still going strong.