The tranny shop says it's not tranny. What possible probable things could cause my truck to start bucking or missing or whatever it is doing after it shifts 4 times and hits 35.

If you respond, please let's keep this going until some resolve. I see to many threads that often go and just die. Never any resolve. I probably have a couple myself and I might have been the last reply.

 

Have you checked the fuel pressure at the RPM where the problem occurs (ie: 1400 rpm) and duplicated the problem? Possible vacuum leak, checked coil and plugs, Air filter, fuel filter, Cat failing and plunging the exhaust. Do you have any codes?
Just throwing things I have seen in the past that could cause the problem in no order of importance.

 

I would check for a vacuum leak.

 

The tranny shop was at a loss, of course with going to deep and charging me who knows how much. Some things the recommended I had already done.

They said something about certain cylinders cross firing. (How could this happen?)

I have not checked fuel pressure at that rpm. However it seems not to be just rpm but also what gear tranny is in.

I have thought about the cat, but I would think that would cause other run ability issues.

Before I got the truck it appears as though there have been a problem with spark plug port and now the OEM plug does not fit. I have to have one with a longer thread. The OEM plug is a copper electrode. The current plugs are platinum. They and the wires have been there since the end of 2011 and probably don't have 40,000 miles on them. Could the plugs and or wires need to be changed? ( at least plug to copper electrode IDK?)

 

I have a vacuum pump that I use for brake bleeding.
What and how do I need to go about checking vacuum?
Where do I make these checks, and how much vacuum should be applied?

Could this be a compression issue?

The truck seems to run like a bat when I floor it. It's just hitting 35 and trying to hold it steady.

 

The previous owner of my 95 had the tranny rebuilt for a similar issue as what you describe but the problem persisted. When I bought the truck, it would run really well sometimes but there were way too many times when there was zero throttle response - no passing gear.

I fixed the vacuum leaks and replaced the TPS. Runs like new now.

 

Have you replaced the stock plastic vacuum lines? If not get some 5/32" tubing from your local shop and go to town. If you have any questions don't hesitate to ask.

http://www.fullsizebronco.com/forum/...es-rubber.html

I seem to remember you tested the TPS and it came back ok.

 

The TPS was a little out on the resistance but it didn't have any dead spots. What the heck I replaced it anyway.

Well I guess the vacuum line replacement (some of those you almost have to pull the intake to get) would still be cheaper, if it fixes it, than replacing plugs and wires.

 

Should EVR hold vacuum?

 

No