I have a 98 F150 V6 4.2L with about 150K miles. I've driving around the last 30k miles with the CHECK ENGINE light ON, and most recent The last 5K with it Turning on and off. I've seen all the posts about the problems with the 97's and early 98's. I have changed pretty much everthing except the engine ( wires, plugs, egr, tps,computer, cleanned the MAF, fuel filter) . I love this truck I bought it new, and struggled 5 years to pay it and I really do not want to sell, but my frustration is driving me crazy

 

What code or codes do you have?

 

i know that some of the 4.2s go over 200, and there are some that might go more, but having a fleet of these things, we rarley see more than 145k or so without a Check Engine LIght issue. They will continue to run for a long time, but none of the management systems, emmissions etc, will function correctly due to blow-by and leaky valve seals, etc. You can chase it all forever.. In fact, the CEL coming on, means the sensors are working, generally.

I have an extra 4.2 that is out and ready for Overhaul. Pay the shipping and you can have it.

 

I can attest to that fact. My '99 made it to 100k with a SES light coming on. Needed new plugs... but it also needed a lot more. (Probably the reason I got rid of it... but it didn't need that much work. At the time, I wanted reliable... never got it with my Escape though... kind of defeated the purpose... lol) However, I did get a complete tune up and the works from my dealer (at that time, I was younger and I wasn't automotive savvy as I am now). Cost me close to $700 if I remember correctly. The service department quoted me with around $350 when I first stopped in... they cut throated me by charging me more than double. Not to mention the truck ran fine for like 1k, and then the SES light came back on. So I felt like I was up against a war. Go to find out a week after I sold it, when I went back to the dealer to pick up my new Escape, the service manager told me that all I needed was a new plug... somehow they didn't gap one correctly. He told me I was stupid for trading it. Go figure. At least the service manager was honest... and then he clarified about why it cost me so much for the tune up. The main reason was the plugs being seized in taking a long time and lots of effort to get them out and how there was more work than usual. Which makes sense. I now know how long it takes to get seized plugs out of an engine even with all of the proper tools necessary. You still need to be careful.

But I think it was kind of rotten how the service manager told me this AFTER I just decided to make myself poor. With the first few major problems with the Escape... I wanted to kill myself.

 

PO122
PO171
PO122 again
PO171 again
I got these codes after putting in a new battery

 

p0171 is telling you that one bank is Lean. a lot of people will tell you you probrably need a o2 sensor, and you might, but it is unlikely. The sensor is probrably doing what it is supposed to do and telling you the mixture is outside of the params it can detect, and more than the ecu can correct.

It is more likely worn piston rings, and various and sundry intake leaks, including the mid to lower manifold bolts, which have been improved by ford. there are 8 of them inside the plenum, and cost about 6-8 dollars each.

Do you have access to a compression gauge? if so, check all of the cylinders, I had two much lower than the others, and isolated the rings using oil in the cylinder. I also had a couple of bad (leaking) intake valves.

If you get into overhauling the motor, my 2 cents of advice would be to not do just the heads, or just the lower end. Do it all, and the truck will give you another 150k plus of service.

 

I just changed the plugs again and for the 1st time the plug in Cylinder #1 was black and all the other ones were nice and clean. can this be the problem? what is an average price for an engine overhaul?

 

From the problems I've seen #1 gives the most problems. The problem is as the engine wears the rods that Ford used [snap rods] will start to egg shape around the crank and wobble in the cylinder. For the check engine light I'm with bradschmidt on the intake leak for code P0171. For code P0122 look for a wiring problem to the TPS, broken wire/ bad connection. If you go with new engine check with motorcraft web site, sometimes they have specials and sometimes the counter guy will cut you a deal at the dealership.

 

Can a pin hole in the tps wiring create the reading PO122?
Thank you very much guys, I think I'm going to get a new engine

 

I have a '97 F150 4X4 4.2L and the Check Engine light has been on a long time. Runs great. I ain't gonna worry about with 98K on the thing. Keep taking care of it as best you can and don't worry. With the cost of new trucks, I drive this thing pretty cheaply. Just put on new plugs, wires, fuel filter, new tires, new Bilstein shocks. She's good to go for a long time. I want a new truck pretty bad but @ $32-$37,000...not right now.

 

take off your upper plenum and replace the plenum gasket and all the vacum lines and elbows beneath it.

 

I need help with my f 150 4.2 1997 code found po122

 

http://www.obd-codes.com/p0122

 

Instead of hijacking a thread that is 3 years old, use the search feature or start a new thread.

glc has pointed you in the right direction though.