Unusual Problem(?)

[moklerman]

I drive a Ford Ranger at work for my restaurant delivery job. They have a handful of trucks, most of which are Ford Rangers. Mine is newer than 2000 and I'm pretty sure it's a 2003.

It's a 4 cylinder, 5-speed, with A/C and has 196,000 miles on it.

Recently, I started it up after my 2 days off and the "check engine" light was on. I drove it that night and didn't have any problems. The next day I took it to a shop that I trust and they said the error code was a fuel/air code and that it might be something as simple as a fuel cap. They reset it and said to bring it back in if it came on again.

It was fine for a couple of days and then the next day, the "check engine" light was on again the first time I got into the truck that day. This time however, the A/C was blowing hot air. The clutch relay had been replaced relatively recently and I assumed it was a bad one and had gone out. But after about 20 minutes of driving, it started working like normal.

That same night though, after about 2 1/2 hours of driving(start and stop driving since I'm doing deliveries) all at the same time the "check gauge" light came on, the truck lurched and the temperature gauge instantly jumped from where it always sits in the middle to all the way pegged to hot. I immediately pulled over and shut off the ignition. I expected to find a burst radiator, blown water pump, timing belt...something, but I couldn't find anything. The coolant reservoir was full and, novice that I am, could not find any obvious problems that should cause the truck to act up.

I started the truck to see if it would start and to see how it was acting and everything seemed to be back to normal. The temperature gauge was back in it's normal spot and it seemed to be running fine. The A/C was blowing cold, it was idling fine and driving fine. I drove about two blocks to my next stop, then on my way back to the restaurant it did the same exact sequence of events. Lurched, gauge spiked, check gauge light came on.

I pulled over, checked everything again, no problems. Started it up, everything seemed normal. As before the "check engine" remained on throughout but the "check gauge" was off, temperature was normal and it was driving fine. This time I turned the A/C off to see if it would help keep it from acting up. No luck. After about a mile, all of it happened again.

This time I parked it and the restaurant said to leave it and they sent a driver to bring me back. It sat over night and the next day they had me drive it back after it had cooled down. I left the A/C off but it seemed to be fine the whole way back of about 15 minutes...until right when I got back to the restaurant. This time, the temperature had been reading really cool. The gauge had move from pegged cold to just above that mark the whole trip back but right when I got back to the parking lot it instantly jumped to half way.

They had their mechanics look at it and they guessed that it was the water pump after hooking some kind of pressure tool onto the coolant reservoir. When hot, it didn't leak but when they tested it cold, it did leak from the water pump with pressure added to the system. The water pump and sending unit were replaced and tested and as far as they could tell, it should have been fine.

The first day I drove it though, it was a repeat of everything that had happened before. The "check engine" light was on at first startup, the A/C ran hot for about 15-20 minutes then got cold, everything seemed fine for about 2+ hours then the lurch, "check gauge", temperature gauge instant spike from medium to pegged hot and shuddering idle. Turn it off, check for signs, nothing, re-start and everything seems fine for a mile or two and then rinse and repeat.

Got it back to the restaurant and it's been sitting for about a week because no one knows what it is.

The one thing I've been able to find online that sounds the most similar but on a different Ford vehicle is related to COP problems(coil on plug) but the mechanic said this truck has just a regular single coil.

Oh, that reminds me, one of the symptoms listed with the COP find was a fluctuating speedometer which I had noticed in the past but hadn't considered a real problem. When sitting at a full stop, the speedometer will lightly bounce from 0-5 mph.

Anyway, I know this was long but I'm trying to be as descriptive as possible. It's 100+ degrees here and my truck is one of the few that has A/C and I'd like to get it running again.

Thanks in advance.

 

[srteach]

Seems to me that everything you mentioned can be related to electrical issues. Possibly regulator or alternator. I believe the regulator is internal to the alternator. I suggest checking there.

 

[moklerman]

Thanks for the reply. I was really hoping that this was something that a lot of people had run into with the Ranger but I've only been able to find a symptom here or a symptom there that are the same with other situations.

They took it to a different shop today and I haven't heard anything. I'm hoping they know their stuff more than the previous two guys who have given it a try. My hope is that it is something electrical and not a blown head gasket or cracked head or any of the other catastrophic possibilities that are out there.

There was no coolant loss though so I hope that means it isn't an internal engine issue.