Need help won't rev past 4-4500

[Lazy706]

Ok here's my problem car runs fine when it's cold revs up all the way up, but when it reaches operating temp it wnt rev past 4-4500 and gets worse the longer it runs. After a while it doesn't even want to start what could be wrong?

[Lazy706]

Check ecu no codes, checked tps, checked the cps all tested good. Tried swapping maf made no difference.

[traxx07]

MAF wiring? Maybe unplug maf and see if it does the same thing. (Warms up and doesnt rev past 4500 with maf unplugged.)

Maybe a sticking injector? Do all the basics. Check plugs, injectors, make sure your getting spark, grounds, etc.

[Lazy706]

Yup tried that still same problem. Imma have to try changing plugs n cables but I am getting spark. Any other ideas on wat I shud check?

[Lazy706]

Question is it possible that my fuel pump is going out and gets weaker the longer I run? I know usually it works or it doesn't but i just want to kno if it's possible?

[s13panic]

Maybe coolant temp sensor? If its getting an inaccurate reading when hot it can possibly either lean out or richen the a/f mixture. Can also cause no start condition when engines hot.

[Lazy706]

Yea I thought that too so I bought a new coolant sensor and swapped it still had the same problem.

[s13panic]

What year and engine is it? KA has 2. One tells gauge what its reading and the other tells ecu what to do.

[Lazy706]

93 and yea I changed the ecu one with 2 pins I believe thats the right one?

[Lazy706]

Srry yea it's ka

[s13panic]

Yea thats the ecu one. Gotta be something else.

[2.5T_/<ouki]

Question is it possible that my fuel pump is going out and gets weaker the longer I run? I know usually it works or it doesn't but i just want to kno if it's possible?

Was exactly my problem when i did my swap. I was experiencing exactly what you are and once i swapped out my fuel pump all hell was unleashed and my baby boosted like no other.

[Lazy706]

Alright I'll try that nxt I got a pump I can put in at home. I'll let uall know if it changes anything.

[PIN GIO 2]

hey hey hey i think that one happened to me before so luck i found ground wire connect firewall between rear cylinder head was loose bolt then tight bolt also make sure check all ground harness.

[Lazy706]

Thnx I'll try that also

[Lazy706]

Well I swapped fuel pump no difference :/. And I tried looking for that ground wire but couldn't find it maybe because it's a de swap?

[Lazy706]

Swapped out distributor and o2 sensor and so far problem has fixed. Not sure which 1 was my problem but Thanx for yalls help.