I have a 1990 Bronco. The problem is when i drive it for a while it starts to lose power when the temp starts to rise of the vehicle. I have done a tune up replaced the TPS, O2 sensor and IAC. Sometimes I can't get out of the way of traffic it is so bad. I can hear a loud whine from the Fuel pump. The hotter it gets the more it skips as I go down the road. After it sits over night it runs great until it gets hot. I would like any and all advice possible to help out.

Thanks

 

Temp sensor maybe?

 

could also be that the fuel pump is on its way out

 

I broke down and got a code scanner, but having trouble using it. After I get the engine code am I supposed to REV the engine up to max and let go?

COnfused?

 

My code reader is an Innova (Wal mart). It gooses the motor when needed. There are two tests, Key On Engine Off (KOEO) and Key On Engine Running (KOER). You're going at the problem the right way. It took me a long time to buy a code reader and it can be a great diagnostic tool. I'd be interested to hear what your problem turns out to be.

 

I think that just about all Broncos have this problem at one time or another. To Note: When I performed at KOEO test I got a code for EGR, but since i didn't know how to use the code scanner i accidently Erased the codes by fiddling with it when trying to crank the truck. I am going to drive it tommorrow and see what happens. Trust me i will be around much.

From what i read The EGR goes out a lot, but so does the IAC, TPS and just about every other damn thing on a FORD

Thanks

 

UPDATE:'''''

I woke up today and drove it to get breakfast. I got the code scanner and put it up to it. KOER test showed CODE 42. I just put a new O2 sensor in the Truck so why would it do this.

One thing i thought of was when the truck is hot or has warmed up perhaps the EGR is not working right. Some times i cannot idle at all in the mornings and sometimes it idles fine. I did notice that the little red ring inside the EGR didn't move when i drove it up the road?>

EGR now?
LOST and confused

 

I have the same problem on my 90. I haven't bought a code scanner yet, I was hoping to avoid that for awhile for financial reasons. Basically the trucks acts up pretty consistently when it's cold or damp out, and only occasionally when it's fair outside. When it running good, it's wonderfull. When it's not, it's terrible and embarrasing. On a bad day, you can start it and it will fire right up, then after about ten seconds just die. After several restarts, it will finally stay running but surge terribly between 400 and 1200 rpm. I can even feel it surging while I'm driving, meaning I can feel it suddenly lose power, then a few seconds later restore. Once I've driven it awhile, it will warm up and get better, but even then if I sit at a long stoplight it will idle nice for a few minutes then suddenly revert to the surging.

It has a very recent tune-up with quality parts, no junk Autozone crap. I recently did all the upper engine gaskets (except the heads) because I had a bad intake gasket. When I did the upper upper engine gaskets, I throughly cleaned the throtle body, IAC and intake runners with carb clean. This was last fall and the truck ran like a Lincoln until this started about 2 weeks ago. I haven't changed anything else, I don't want to just throw parts at it. I suspect a few things could cause this though. I suspect the fuel pressure regulator, fuel filter, IAC and maybe something in the ignition. I guess I could even see a bad fuel pump causing some of these problems.

I would love to hear some ideas about which way to go.

-Jimmy

 

I had the same problem and it turned out to be the feul pressure regulator diaphram was shot and sucking raw fuel into the intake thru the vac. line I changed it out no problem 55.00 at autozone its right on the fuel rail drivers side good luck peter

 

I had something similar, to where I could not get my RPM's up past 3k without it sputturing like there was some kind of fuel shut off. Under 2500 rpms it ran great, until I try to get it above that. It started when my ignition module on the distributor went bad. I replaced the fuel pump, ignition module, fuel pump regulator, Fuel filter, and new distributor, Still I had no luck on solving my problem. I then upgraded the computer to Mass Air flow from the old speed density setup. I haven't had the problem since.

Which worked for me, I'm still not sure. But my rig runs great now. It could have been just replaceing just the computer and the ignition module. The Code scanner helped some what.

So it is sometimes hard, even with code scanner, to pin point exactly what the problem is. If I did not love my Bronco, the beast of burdon that it is, I would have scraped it long ago.