I just got my 98 Discovery (100,000 miles) back from a mechanic I had asked to change my fuel injectors. I replaced them because I was having trouble getting it started on cold mornings. Also, I felt that it seemed to be sluggish.

He called me when it was done as asked why I wanted the injectors replaced and I told him about the hard starting. He agreed that should help, but thenhe asked if the exhaust was “popping” before. I said no, and he said, “Well, it does now.”

When I picked it up it, the check engine light was on. I can’t believe he didn’t check it out before I picked it up. I guess I won’t be going back to him. Anyway, I got it home and scanned it. It was a P1316 misfire code and I cleared it and it hasn’t come back. I’m not sure what he meant by the popping sound, but the sound of my exhaust on my truck hasn’t seemed right for a while.

Could this be the “sticky exhaust valve” problem I’ve seen on some posts or could it be related to the catalytic converters? If you think it could be the sticky valve problem, would the ATF engine flush help or do I have to have someone do a valve job on it? It has a slight ticking when I start it, but it goes away quickly.

The changing of the injectors seems to have helped with starting and with the sluggishness, but the idle isn’t as smooth as it used to be. Any ideas?

 

You might want to stop throw money at you truck, the injectors were not needed unless you had a series of injector faults.
Have you changed your fuel filter, have you had your fuel pressure tested, normally the pump is the problem for hard cold starts.

 

Thanks Disco Mike

I had a new fuel filter put on the same day as the injectors were replaced. I did not have the fuel pressure tested however. It's due for inspection in a couple of weeks and I'll have it done then.

Any input on the exhaust? It just seems to be constricted. What do you think of the ATF engine flush? Will that help unstick exhaust valves? Was the sticky valve problem predominately found in the 3.9 engines as opposed to my 4.0?

 

X2 on replacing the injectors. What!!!! Replacing injectors for cold starting is crazy. You might want to remember that you can buy injector cleaner for the future

 

Well, guess what, nice cold morning here and Disco started as if it was 90 outside. I seem to remember someone on this forum suggesting that injectors should be replaced around 100K, so I did. Didn't replace them with that Lucas overpriced crap either.

As far as using injector cleaner, I always had theshop where I get my oil changes add it. So I regularly used it every 3,000 miles.

Thanks for the help.

 

O2 sensors, not injectors... They start to go around 80k.