engine hesitates on accelaration

[jsj123]

I have been lurking for several weeks, now my SHO is not running right. It is a 91 with 142K miles. The last 60k was done @ 90k according to the prior owner.

When the engine is warm, and I press the gas, the engine will act as if it is lugging or missing. It has become very difficult to take off from a stop. When I accelerate hard, it hesitates until I get over 3500 rpm.

I pulled codes today and only got a 24. I tried to get the fuel pressure, but I either have 0 psi at idle, or my cheap harbor freight fuel pressure gauge does not work .

Where should I start looking? It doesn't happen when the engine is cold.

-Stephen

 

[thecrew2999]

that gauge isnt working heres what everything should be


Refer to the Engine/Emissions Facts Book and Calibration number.
FUEL PRESSURE SPECIFICATIONS
ÚÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÂÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ¿
³ Description ³ Specification ³
ÃÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÅÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ´
³ Engine Running ³ 30-45 psi ³
³ ³ 210-310 kPa ³
ÃÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÅÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ´
³ Key ON Engine OFF ³ 37-43 psi ³
³ ³ 255-297 kPa ³
ÀÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÁÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÙ

 

[thecrew2999]

o yeah also if you wind up needing a fuel pump i got a walbro im gonna part with

 

[jsj123]

My diagnostic skills are terrible. I took the car to a mechanic and they pulled codes for oxy sensor and coolant temp sensor. Replaced the coolant temp tonight, may not get to the oxy sensors till the weekend.

This will sound lame, but I have a really nice heated garage with a painted floor, and I want to mop out the filth from last weekends snow storm before I start crawling under the car.

Do you guys use a O2 sensor wrench? Also, do you clear the computer after replacing the sensors?

--Stephen

 

[SHOck]

Those that that balk at a nice, warm garage are just jealous. I've been telling them for years!

A special wrench is not required for the O2's, unless you want. I use a wrench, or maybe it was an adjustable wrench, can't remember.

Clear the codes after you replace the O2's. Might want to let the car re-learn idle, too.

Great hesitation at throttle tip-in is a sign of a dirty MAF or bad TPS. I'd shoot for cleaning the MAF first to ensure it is not an issue, then troubleshoot from there.

David

 

[jsj123]

I noticed there was some orange goop on the threads of the old coolant sensor, is thread tape ok on it?

Where are the oxy sensors documented in the Ford Shop manual? I looked all over the index. Plus where are the codes documented, again I could not find it in the manual.

Thanks for any help.

--Stephen

 

[projectSHO89]

The replacement ECT sensor should come out of the box with thread sealant on it. If not, teflon tape is fine as long as it's put on so none can break loose and float away inside the system.

Codes are documented in the PCED manual, not the shop manual. If you have a hard-copy manual, it's a separate book. If you have the CD, it's on there.


Steve